Start reading the pinned threads on Beginners & help and Meta. These will help you.

Beginners and help: https://bitcointalk.org/index.php?board=39.0
Meta: https://bitcointalk.org/index.php?board=24.0

Important ones are:
Unofficial list of (official) Bitcointalk.org rules, guidelines, FAQ
Forum ranks/positions/badges (What do those shiny coins under my name mean?)
Merit and activity system