Tutorial Or How-To, To Install Usergroups

Hi,

I have a little problem with the instalation of the module or extension of usersGroups, in fact, i follow the step of this link,

http://www.yiiframework.com/extension/usergroups

But when i want to check the application in the browser, got a 404 error, and want to know, if someone know some tutorial o how to more easy to install this extension.

Thank you for your attention.

Mike