first.install

<?php
/**
 * Implements hook_install(). 
 */
function first_install() {
    variable_set('first_default_centre_lat', -75.569851);
    $t = get_t();
    drupal_set_message($t('first variables created'));
    /**
     * content type definition
     */
    $content_type = array(
        'type' => 'first',
        'name' => $t('first'),
        'description' => $t('a first module content type'),
        'title_label' => $t('first name'),
        'base' => 'node_content',
        'custom' => TRUE,
    );
    $node_type = node_type_set_defaults($content_type);
    //save the content type
    node_type_save($node_type);
    //add body field 
    node_add_body_field($node_type, $t('description'));
    //add fields
    $fields = array();
    $fields['first_field'] = array(
      'field name' => 'first field1',
        'type' => 'number_integer',
        'cardinality' => 1,
        'settings' => array(
            'max_length' => 5,
        )
    );
    $fields['second_field'] = array(
      'field name' => 'Second field1',
        'type' => 'number_float',
        'cardinality' => 1,
        'settings' => array(
            'max_length' => 5,
        )
        );
        foreach ($fields as $field) {
            field_create_field($field);
        }
    
}
/**
 * implements hook_uninstall
 */
function first_uninstall() {
    variable_del('first_default_centre_lat');
    $t = get_t();
    drupal_set_message($t('first variables deletedd'));
}