I arrived at the venue for the 'registration event' and was told where to go. Then registered my attendance with a polite lady. Then told to wait to be called, which took less than a minute. Handed documents over and asked which shift I'd like, then sent to wait to for another person, which took less than five minutes. Given job offer there and then, subject to security check, photo taken for ID and that was it. Very simple process, just make sure you have all relevant documents and it'll take no more than 20-30 mins. Would also recommend booking the earliest slot possible because the shifts are given on a first come first served basis. In regards to what to wear, I wore smart shoes, trousers, shirt but in all honesty there were people in jeans and t-shirt so you'd get away with that.