How to properly set up friendly URLs?

[Smokey-Rev]

Can someone guide me how to properly set up friendly URLs on my forum?

 

Whenever I enable he two options in the admin CP it gives me 404 errors on most pages, what does my HTACCESS need to look like to get the pages rewritten properly if a forum lives at

 

http://site.com/boards

and I want a main page using Pages at www.site.com 

 

please advise.  

 

Here is a screenshot, can someone explain how to do this? I'm on shared hosting.