Good luck. Remember, they piss test you during this.
When I went, everything went swimmingly until I took the test for color blindness. I'm not color blind but I have a slight color deficiency, and that made all the difference. I hope the same doesn't happen to you. And I just remembered, drive yourself. DON"T let them put you up in a hotel, it's always a glorified crackhouse.
You don't say what branch you're joining, but if they don't give you the job you want, don't sign anything until you talk with the other branches. That's what I should have done.