diff --git a/.gitignore b/.gitignore
index c33bf252..ecdaea19 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,6 +14,7 @@
 !/tmp/.keep
 .DS_Store
 capybara-*
+.vscode/
 
 # Ignore Byebug command history file.
 .byebug_history
diff --git a/app/assets/stylesheets/application.css b/app/assets/stylesheets/application.css
index b238693d..e17dadb4 100644
--- a/app/assets/stylesheets/application.css
+++ b/app/assets/stylesheets/application.css
@@ -497,3 +497,79 @@ nav.email-templates-menu li a:hover {
 input.grey {
   background-color: #c4220d;
 }
+
+.grid-wrapper {
+  display: grid;
+  grid-template-columns: 200px 200px 200px;
+  margin-bottom: .5em;
+}
+
+.info-wrapper {
+  display: flex;
+  /* justify-content: space-evenly; */
+  margin-bottom: 1em;
+  font-weight: bold;
+  color: #fff;
+}
+
+.info-wrapper .info {
+  border-right: 1px solid #ffff;
+  padding: 15px;
+  text-align: left;
+  width: 30em;
+}
+
+.cc-gradient {
+  background: linear-gradient(to right, #28B4F0, #F0A0C8);
+}
+
+.cc-gradient-reverse {
+  background: linear-gradient(to right, #F0A0C8, #28B4F0);
+}
+
+.tag {
+  padding: 0 .7em;
+  font-size: 12px;
+  width: fit-content;
+  color: #fff;
+  border-radius: 5px;
+}
+
+/* Printer styles */
+
+@media print {
+  header,
+  input,
+  footer,
+  .top-menu {
+    display: none;
+  }
+
+  body {
+    color: #000;
+    background-color: #fff;
+  }
+
+  .container {
+    width: 100%;
+  }
+
+  table {
+    break-inside: avoid;
+  }
+
+  h2 {
+    page-break-inside: avoid;
+    margin-top: 30px;
+  }
+
+  /* Hacky solution to make avoidance of page break work ^^
+  https://stackoverflow.com/a/53742871/9328428
+  */
+  h2::after {
+    content: "";
+    display: block;
+    height: 200px;
+    margin-bottom: -200px;
+  }
+}
\ No newline at end of file
diff --git a/app/controllers/admin/groups_controller.rb b/app/controllers/admin/groups_controller.rb
index 69175778..768876a1 100644
--- a/app/controllers/admin/groups_controller.rb
+++ b/app/controllers/admin/groups_controller.rb
@@ -3,15 +3,116 @@ class Admin::GroupsController < ApplicationController
   before_action :require_admin
   before_action :find_event
 
+  GROUP_SIZE = 4
+
   def index
+    @event_groups = @event.event_groups
+    @coaches_count = @event.coach_applications.approved.size
+    @attendees_count = @event.applications.application_selected.size
   end
 
+  # An action to regenerate
+  # -> a controller method
+  # -> button (to call the action)
+  # -> a route
+  # -> isolate generate behaviour in its own method
+
   def generate
+    fill_groups
+    @event_groups = @event.event_groups
     redirect_to admin_event_groups_path(@event), notice: "Groups successfully generated"
   end
 
+  def regenerate
+    @event_groups = @event.event_groups
+    @event_groups.destroy_all
+    @event.reload
+
+    fill_groups
+    redirect_to admin_event_groups_path(@event), notice: "Groups successfully regenerated"
+  end
+
   private
 
+  def fetch_by_key(object, key)
+    object[key] || []
+  end
+
+  def fill_groups
+    # create a group for each pair of coaches
+    @coaches = @event.coach_applications.approved.to_a
+    @coaches.each_slice(1).with_index do |group, index|
+      event_group = EventGroup.create(event: @event, name: "Group #{index + 1}")
+      group.each do |coach_application|
+        event_group.coach_applications << coach_application
+      end
+    end
+
+    # get selected attendees from DB
+    @attendees = @event.applications.application_selected.confirmed.to_a
+
+    grouped_attendees_by_language = @attendees.group_by do |element|
+      [element.language_de, element.language_en, element.os]
+    end
+
+    attendees_de_mac = fetch_by_key(grouped_attendees_by_language, [true, false, "mac"])
+    attendees_de_windows = fetch_by_key(grouped_attendees_by_language, [true, false, "windows"])
+    attendees_de_linux = fetch_by_key(grouped_attendees_by_language, [true, false, "linux"])
+
+    attendees_en_mac = fetch_by_key(grouped_attendees_by_language, [false, true, "mac"])
+    attendees_en_windows = fetch_by_key(grouped_attendees_by_language, [false, true, "windows"])
+    attendees_en_linux = fetch_by_key(grouped_attendees_by_language, [false, true, "linux"])
+
+    attendees_de_en_mac = fetch_by_key(grouped_attendees_by_language, [true, true, "mac"])
+    attendees_de_en_windows = fetch_by_key(grouped_attendees_by_language, [true, true, "windows"])
+    attendees_de_en_linux = fetch_by_key(grouped_attendees_by_language, [true, true, "linux"])
+
+    attendees_de_mac_groups = attendees_de_mac.in_groups_of(GROUP_SIZE, false)
+    attendees_de_windows_groups = attendees_de_windows.in_groups_of(GROUP_SIZE, false)
+    attendees_de_linux_groups = attendees_de_linux.in_groups_of(GROUP_SIZE, false)
+    attendees_en_mac_groups = attendees_en_mac.in_groups_of(GROUP_SIZE, false)
+    attendees_en_windows_groups = attendees_en_windows.in_groups_of(GROUP_SIZE, false)
+    attendees_en_linux_groups = attendees_en_linux.in_groups_of(GROUP_SIZE, false)
+
+    [attendees_de_mac_groups, attendees_en_mac_groups].each do |groups|
+      if groups.try :nonzero?
+        if (groups.last.size < GROUP_SIZE)
+          groups.last.concat(attendees_de_en_mac.pop(GROUP_SIZE - groups.last.size))
+        end
+      end
+    end
+
+    [attendees_de_linux_groups, attendees_en_linux_groups].each do |groups|
+      if groups.try :nonzero?
+        if(groups.last.size < GROUP_SIZE)
+          groups.last.concat(attendees_de_en_linux.pop(GROUP_SIZE - groups.last.size))
+        end
+      end 
+    end
+    
+    [attendees_de_windows_groups, attendees_en_windows_groups].each do |groups|
+      if groups.try :nonzero?
+        if(groups.last.size < GROUP_SIZE)
+          groups.last.concat(attendees_de_en_windows.pop(GROUP_SIZE - groups.last.size))
+        end
+      end
+    end
+
+    de_en_groups_mac = attendees_de_en_mac.in_groups_of(GROUP_SIZE, false)
+    de_en_groups_windows = attendees_de_en_windows.in_groups_of(GROUP_SIZE, false)
+    de_en_groups_linux = attendees_de_en_windows.in_groups_of(GROUP_SIZE, false)
+
+    all_groups = attendees_de_mac_groups + attendees_de_windows_groups + attendees_de_linux_groups + attendees_en_mac_groups + attendees_en_windows_groups + attendees_en_linux_groups + de_en_groups_mac + de_en_groups_windows + de_en_groups_linux
+
+
+    # FIXME: This can cause attendees to not be assigned to event groups
+    @event.event_groups.each do |event_group|
+      group_to_add = all_groups.pop(1) 
+      break if group_to_add.nil?
+      event_group.applications << group_to_add
+    end
+  end
+
   def find_event
     @event = Event.find(params[:event_id])
   end
diff --git a/app/models/application.rb b/app/models/application.rb
index 43c2aefc..d05ad55c 100644
--- a/app/models/application.rb
+++ b/app/models/application.rb
@@ -21,6 +21,7 @@ class Application < ApplicationRecord
   scope :cancelled, -> { where(state: :cancelled) }
   scope :not_marked_as_selected, -> { where(selected_on: nil) }
   scope :confirmed, -> { where(attendance_confirmed: true) }
+  scope :language_de, -> { where(language_de: true) }
 
   enum state: { rejected: 0, waiting_list: 1, application_selected: 2, cancelled: 3 }
 
diff --git a/app/models/coach.rb b/app/models/coach.rb
index ff6ce02d..cd7cf2c3 100644
--- a/app/models/coach.rb
+++ b/app/models/coach.rb
@@ -3,4 +3,5 @@ class Coach < ApplicationRecord
   belongs_to :user
   accepts_nested_attributes_for :user
   has_many :coach_applications
+  has_and_belongs_to_many :event_groups
 end
diff --git a/app/models/coach_application.rb b/app/models/coach_application.rb
index e6c195ce..01cbf0cb 100644
--- a/app/models/coach_application.rb
+++ b/app/models/coach_application.rb
@@ -5,6 +5,7 @@ class CoachApplication < ApplicationRecord
   accepts_nested_attributes_for :event
 
   scope :to_contact, -> { where(contacted_at: nil, state: :approved) }
+  scope :approved, ->{ where(state: :approved) }
 
   enum state: { pending: 0, approved: 1, rejected: 2, cancelled: 3 }
 
diff --git a/app/models/event.rb b/app/models/event.rb
index 0fc10e9f..4f05e0ef 100644
--- a/app/models/event.rb
+++ b/app/models/event.rb
@@ -1,6 +1,7 @@
 class Event < ApplicationRecord
   has_many :applications
   has_many :coach_applications
+  has_many :event_groups
   before_create :copy_templates
 
   validates :name, :place, :scheduled_at, :application_start, :application_end, :confirmation_date, :start_time, :end_time, presence: true
@@ -26,9 +27,9 @@ def name_and_date
   end
 
   def has_groups?
-    false
+    !event_groups.empty?
   end
-  
+
 private
 
   def right_order_of_dates
diff --git a/app/models/event_group.rb b/app/models/event_group.rb
new file mode 100644
index 00000000..f1ab6678
--- /dev/null
+++ b/app/models/event_group.rb
@@ -0,0 +1,5 @@
+class EventGroup < ApplicationRecord
+  belongs_to :event
+  has_and_belongs_to_many :coach_applications, join_table: "event_groups_coach_applications"
+  has_and_belongs_to_many :applications, join_table: "event_groups_applications"
+end
diff --git a/app/views/admin/groups/index.html.erb b/app/views/admin/groups/index.html.erb
index b057b590..3ff358c1 100644
--- a/app/views/admin/groups/index.html.erb
+++ b/app/views/admin/groups/index.html.erb
@@ -1,5 +1,71 @@
 <% if @event.has_groups? %>
-has Groups
+
+  <div class="info-wrapper cc-gradient">
+    <div class="info">Attendees: <%= @attendees_count %></div>
+    <div class="info">Coaches: <%= @coaches_count %></div>
+  </div>
+  <%= button_to "Regenerate groups", regenerate_admin_event_groups_path(@event), method: :post %>
+  <% @event_groups.each do |event_group| %>
+    <h2><%= event_group.name %></h2>
+    <table>
+      <thead>
+        <tr>
+          <th>Attendees</th>
+          <th>Coaches</th>
+        </tr>
+      </thead>
+      <tbody>
+        <tr>
+          <td>
+            <% event_group.applications.map do |application| %>
+              <div class="grid-wrapper">
+                <span>
+                  <%= application.name %>
+                </span>
+                <span class="tag cc-gradient">
+                  <% if application.language_de === true && application.language_en === true %>
+                    both languages
+                  <% elsif application.language_de === true && application.language_en === false %>
+                    German
+                  <% else %> 
+                    English
+                  <% end %>
+                </span>
+                <span class="tag cc-gradient-reverse">
+                  <% if application.os === "mac" %>
+                    Mac
+                  <% elsif application.os === "windows" %>
+                    Windows
+                  <% elsif application.os === "linux" %>
+                    Linux
+                  <% end %>
+                </span>
+              </div>
+            <% end %>
+          </td>
+          <td>
+            <% event_group.coach_applications.map do |application| %>
+              <div class="grid-wrapper">
+                  <span>
+                    <%= application.coach.name %>
+                  </span>
+                  <span class="tag cc-gradient">
+                    <% if application.coach.language_de === true && application.coach.language_en === true %>
+                      both languages
+                    <% elsif application.coach.language_de === true && application.coach.language_en === false %>
+                      German
+                    <% else %> 
+                      English
+                    <% end %>
+                  </span>
+                </div>
+            <% end %>
+          </td>
+        </tr>
+      </tbody>
+    </table>
+  <%end %>
+
 <% else %>
   <%= button_to "Generate groups", generate_admin_event_groups_path(@event), method: :post %>
 <% end %>
diff --git a/config/routes.rb b/config/routes.rb
index 084e2cd4..6ea8a91e 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -49,6 +49,7 @@
       resources :groups, only: [:index] do
         collection do
           post :generate
+          post :regenerate
         end
       end
       put :complete
diff --git a/db/migrate/20200423182041_change_event_group_coaches_to_event_groups_coaches.rb b/db/migrate/20200423182041_change_event_group_coaches_to_event_groups_coaches.rb
new file mode 100644
index 00000000..59e2725b
--- /dev/null
+++ b/db/migrate/20200423182041_change_event_group_coaches_to_event_groups_coaches.rb
@@ -0,0 +1,5 @@
+class ChangeEventGroupCoachesToEventGroupsCoaches < ActiveRecord::Migration[5.2]
+  def change
+    rename_table :event_group_coaches, :event_groups_coaches
+  end
+end
diff --git a/db/migrate/20200423182618_change_event_group_attendees_to_event_groups_applicants.rb b/db/migrate/20200423182618_change_event_group_attendees_to_event_groups_applicants.rb
new file mode 100644
index 00000000..d5405e67
--- /dev/null
+++ b/db/migrate/20200423182618_change_event_group_attendees_to_event_groups_applicants.rb
@@ -0,0 +1,5 @@
+class ChangeEventGroupAttendeesToEventGroupsApplicants < ActiveRecord::Migration[5.2]
+  def change
+    rename_table :event_group_attendees, :event_groups_applications
+  end
+end
diff --git a/db/migrate/20200429185626_change_event_groups_coaches_to_event_groups_coach_applications.rb b/db/migrate/20200429185626_change_event_groups_coaches_to_event_groups_coach_applications.rb
new file mode 100644
index 00000000..630ebe48
--- /dev/null
+++ b/db/migrate/20200429185626_change_event_groups_coaches_to_event_groups_coach_applications.rb
@@ -0,0 +1,5 @@
+class ChangeEventGroupsCoachesToEventGroupsCoachApplications < ActiveRecord::Migration[5.2]
+  def change
+    rename_table :event_groups_coaches, :event_groups_coach_applications
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index ce065c54..4c02f9e6 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2020_02_24_192634) do
+ActiveRecord::Schema.define(version: 2020_04_29_185626) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -71,30 +71,30 @@
     t.index ["user_id"], name: "index_coaches_on_user_id"
   end
 
-  create_table "event_group_attendees", force: :cascade do |t|
-    t.bigint "application_id"
-    t.bigint "event_group_id"
+  create_table "event_groups", force: :cascade do |t|
+    t.bigint "event_id"
+    t.string "name"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.index ["application_id"], name: "index_event_group_attendees_on_application_id"
-    t.index ["event_group_id"], name: "index_event_group_attendees_on_event_group_id"
+    t.index ["event_id"], name: "index_event_groups_on_event_id"
   end
 
-  create_table "event_group_coaches", force: :cascade do |t|
-    t.bigint "coach_application_id"
+  create_table "event_groups_applications", force: :cascade do |t|
+    t.bigint "application_id"
     t.bigint "event_group_id"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.index ["coach_application_id"], name: "index_event_group_coaches_on_coach_application_id"
-    t.index ["event_group_id"], name: "index_event_group_coaches_on_event_group_id"
+    t.index ["application_id"], name: "index_event_groups_applications_on_application_id"
+    t.index ["event_group_id"], name: "index_event_groups_applications_on_event_group_id"
   end
 
-  create_table "event_groups", force: :cascade do |t|
-    t.bigint "event_id"
-    t.string "name"
+  create_table "event_groups_coach_applications", force: :cascade do |t|
+    t.bigint "coach_application_id"
+    t.bigint "event_group_id"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.index ["event_id"], name: "index_event_groups_on_event_id"
+    t.index ["coach_application_id"], name: "index_event_groups_coach_applications_on_coach_application_id"
+    t.index ["event_group_id"], name: "index_event_groups_coach_applications_on_event_group_id"
   end
 
   create_table "events", id: :serial, force: :cascade do |t|
@@ -149,9 +149,9 @@
 
   add_foreign_key "coach_applications", "coaches"
   add_foreign_key "coach_applications", "events"
-  add_foreign_key "event_group_attendees", "applications"
-  add_foreign_key "event_group_attendees", "event_groups"
-  add_foreign_key "event_group_coaches", "coach_applications"
-  add_foreign_key "event_group_coaches", "event_groups"
   add_foreign_key "event_groups", "events"
+  add_foreign_key "event_groups_applications", "applications"
+  add_foreign_key "event_groups_applications", "event_groups"
+  add_foreign_key "event_groups_coach_applications", "coach_applications"
+  add_foreign_key "event_groups_coach_applications", "event_groups"
 end