Forum:Noob questions

Very new to this Battlefield game (I've only just started playing it--Bad Company 2, specifically), and I keep hearing about gold bars online. Can't find anywhere that tells me what they are for, though.

Also, can you collect dog tags in multiplayer? How do you collect them?

In multiplayer, sometimes there's a red rectangle over an enemy and sometimes there's not. I can't tell why it's only sometimes there, though. Anybody know?

And in Rush multiplayer mode...yeah, I just can't figure out the goal. I'm supposed to destroy bases or something, but I never see bases.

And in multiplayer mode it asks me if I want to join a SQUAD. What is this, and what are the pros and cons of joining one?

Obviously a noob, as I said.