How to use drupal cms well? Learn Drupal , Modules, Drupal Themes design

Go http://drupal.org/project/subdomain, download the subdomain module

1. upacked the module, upload to sites/all/modules
2. before enable it, you must edit your setting.php  ( in your sites/default/setting.php line 305)
   changen # $cookie_domain = 'example.com'; to
   $cookie_domain = 'yourdomain.com';
3. upload the new setting.php
4. enable subdomain module