nas table

Hello, I am a new user trying to set up FreeRadius on Fedora 5. I purchased a copy of Hassell's Radius book; didn't seem to help much. I was able to get it to work with clients.conf Then, I converted to MySQL. I think I'm supposed to copy the clients into the nas table, so I did that, but the table doesn't appear to be being used. What do I have to do to use the table? Am I supposed to be using the table? Cliff