diff --git a/README.md b/README.md
index b12a4fd..ec93967 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,72 @@ _Warning: EthVPN is only in alpha stage.  Don't use it for anything important._
 # ethvpn
 The package for running a VPN connection with ShadowSocks via Ethereum.
 
+# Usage
+## Step 1. Connect to Rinkeby testnet
+The `ethvpn` contract is currently deployed on Rinkeby testnet at this address `0x71f3abc045c3e73010ef46042553c66bb7f7a320`. Thus, you need to sync your node to Rinkeby testnet before using the client. Follow the instructions to sync with Rinkeby here https://www.rinkeby.io/
+
+## Step 2. Start your node
+You need to start your fullnode with `rpc` and the  "db,eth,net,web3,personal" rpc-apis enabled. Particularly, since currently only Geth supports Rinkeby, you need to run:
+
+```
+geth --rinkeby --datadir=.rinkeby --ethstats='ethvpn:Respect my authoritah!@stats.rinkeby.io' --bootnodes=enode://a24ac7c5484ef4ed0c5eb2d36620ba4e4aa13b8c84684e1b4aab0cebea2ae45cb4d375b77eab56516d34bfbd3c1a833fc51296ff084b770b94fb9028c4d25ccf@52.169.42.101:30303?discport=30304 --rpc --rpcapi "db,eth,net,web3,personal"
+```
+
+## Step 3. Change your pass-phrase to unlock your account
+The client is using the first address, e.g. `eth.accounts[0]`, so you need to replace the `ethvpn` value in this line
+```
+unlockpassword = "ethvpn"
+```
+to your pass-phrase to unlock the first address.
+
+## Step 4. Run the client.
+
+Simply run
+```
+cd contracts
+python client.py
+```
+It will ask you to key in the command and the corresponding parameters.
+Currently we support the following commands (all indexes start from 0).
+
+1. `list-vpns`, to list all available VPNs, expecting 0 argument.
+Output: a list of `n` tuples, each represent the following info of a VPN:
+```
+string IPAddr, uint bandwidth, string country, address owner, uint maxUsers, uint currUsers, bool accepting, uint fare
+```
+2. `register`, to register a new vpn, expecting 6 arguments: IP, bandwidth, region, maxuser, accepting, fare per hour
+e.g.
+```
+command: register 127.0.0.1 100 Singapore 10 1 100
+```
+3. `list-reqs`, to list all request to rent a VPN.
+Return a list of `m` tuples, each represents the following info of a request:
+```
+uint VPNIndex, uint amount, address user, bool approved, string loginInfo, bool terminated (if approved)
+```
+4. `send-req`, to send a request to rent a VPN, expecting 2 arguments VPN index and the deposit amount (in ETH).
+e.g.
+```
+command: send-req 0 0.1
+```
+5. `acc-req`, for the vpn's owner to accept a request, expect 2 arguments: request index and the login-info
+e.g.
+```
+command: acc-req 0 username-password
+```
+
+6. `close-contract`, for a user to close a contract that was started by him/her (A request is approved will be called a contract.)
+e.g.
+```
+command: close-contract 0
+```
+
+---
+
+```
+geth --networkid=4 --datadir=your-data-dir --syncmode=light --ethstats='ethvpn:Respect my authoritah!@stats.rinkeby.io' --bootnodes=enode://a24ac7c5484ef4ed0c5eb2d36620ba4e4aa13b8c84684e1b4aab0cebea2ae45cb4d375b77eab56516d34bfbd3c1a833fc51296ff084b770b94fb9028c4d25ccf@52.169.42.101:30303?discport=30304 --rpc --rpcapi "db,eth,net,web3,personal"
+```
+