To install Mollom:

 1. Download the Mollom module from http://drupal.org or http://mollom.com
 2. Go to http://mollom.com
 3. Create a new user account if you haven't one already
 4. Login with your mollom.com account
 5. Go to the site manager to create a new key pair for your website
 6. Install the Mollom module on your site
 7. Go to the Mollom settings page and enter the key pair
 8. Configure the Mollom module

For support go to http://mollom.com/support