Heeeeey!~ We'd love to help you out and show you around the forums, if you want to! And welcome to the forums! Pleasure to meet you! \(^▽^*)
Well, you don't really have to decide on what to do right now; for now, you can just explore and pass by each board to see what you like, and then once you feel settled in, you can start posting on wherever you please! General Chat is a good place to start with because it's filled with people who likes to chat about, well, general topics about life and such! Of course, there's always our pokemon topics too, like Battling and Team Battling if you're into competitive, as well as Poekmon General for generalized pokemon discussion!
That and more is just waiting for ya, so, feel free to part-take whenever you please! Have fuuuun, and lovely, lovely times are sure to await you! May we meet again soon to chat! o/