Welcome to The Rebel Faction; use at your own risk. (See, Beff, I got it right that time...)
Read the Rules and FAQ, if you haven't already. Then read them again, and if you have any questions, PM me, Beff Pike, Omnae...or any of the others that seem pretty active. Then read Cataclysm; it gives a pretty good idea of where the storyline in TRF is at the moment.
And Ahnk is right about it being hard; I decided not to read threads when I started and got blasted by Beff when I tried to take over Mandalore, not realizing that there were already a number of RPs about the planet. Don't trust the planets list, or the map for that matter. Always do a Battlegrounds Forum search for the planet's name if you want to do anything with it - trust me, it helps.
Other than that, the best thing for a new member to do is write a bio and join a Faction. I advocate the Empire, but that's just because I'm a member. There are a lot of good, well established factions out there that are more than willing to help new members get involved and learn the ropes. Later, once you really know what you're doing, freelance is OK, but it's best to start with an established faction.
On the other hand, freelancing is OK too, if you're brave enough. We'll still all help you get started, but you won't have that direct backing of veteran members.
Other than that, enjoy yourself!
Oh, and if you see a lot of us going around and insulting one another, know that we don't (usually) mean it. TRF is a well-established community with its own quirks. One of them is that a lot of the members have been around so long that they just got so used to insulting each other that they didn't want to stop. So there's nothing personal. Usually.