Very simple. Show up take ID picture, pass drug test(I think) and nothing else to it. There's usually a long line of people when you show up but that's not normal, Amazon hires in batches.

20-30 ppl interview at certain time intervals by filling out application and speaking with one of the hiring personnel at which time they offer you a position that you must sign off on stating you will be offered this position as long as you pass background check and drug screen.