n00b Questions...

[Buddha]

if you mean you'd like to know which templates affect which segments of the pages, you can do 1 of 2 things.

1. turn on the templates names in the options and then check the page source of various pages as you surf through your forum. that will give you a good idea of what goes where.
2. mess around like crazy. that's what i did, and it was the best way to learn. i applied a ton of hacks and by the time i was done, i knew where things were, and that made it easier to modify the site then.

helps if you have quite a bit of html knowledge, so you're not lost in the code.

good luck.