BuddyPress.org

For more specific help you’d need to give more specific details –

i want to do all sorts of things to profile fields…..

… is a bit vague.

Also, you’re effectively asking someone to teach you how to write code. What you’re after probably requires a more in-depth answer than you’re likely to get here in the forums.

Perhaps you ought to download and break down / delve into the custom profile filters plugin and start from there – that’s an example of how to do these things in code – combined with the codex etc should get you started.