// Get AdWordsUser from credentials in "../auth.ini"
// relative to the AdWordsUser.php file's directory.
$user = new AdWordsUser();
The $user is simply the in-memory representation of the information you set up in auth.ini.
If you are getting no results, then maybe it's because you have no campaigns. Try running the AddCampaigns example first, then this example again.
Regards,
Mike, AdWords API Team