You might also try the
FAQ .
There's plenty of good information there about basic PT stats. The other link (PT forum) provided will have more in-depth information. (Great purchase, BTW. It will help your game immensely.)
I just installed PokerAceHUD, and I'm very pleased. (Thanks NateDog!) If you want to change which stats to display, you'll need to edit the layout. Just choose Options > Layout Manager. There you can select which stats to view, what color ranges, accuracy, and where you want to see them. The feature I love is that you can see mucked hands immediately. (Trust me, it's sweet.)
Good luck!