Mods/Adjustments to a 93 se...please help

This is not a thread asking why a bigger exhaust works, etc. I'm here to find out about advancing/retarding the "timing". I've read a lot of general things about this "easy/costless" mod, basically saying "you should advance your timing", so I haven't really come across specifics. First, I'm not positive on what this mod actually is. Is it something to do with the cams/shaft whatever? Is this something you adjust yourself, or have a shop do. Basically anything anyone has to say about this particular adjustment would be greatly appreciated. Thanks in advance.
Louis

reason for edit: I decided to keep this post about timing adjustments. earlier, I was rambling on about how frusterated I am with Maxima.org. Hopefully this will keep this thread "on focus"
Thanks

can any 3rd gen. expert help out on this issue, or at least link me to a place that explains this mod?