You'll be presented an individual case study and given 20-30 mins to prepare. There is no real way to prepare to these as the possibility of problems presented to you are endless. However, few things I'll suggest you do (I'm sure you've heard this 100 times already) is to try to break your problem down and most important of all give your answers in a structured way (I learnt the hard way).
After this you'll probably discuss the case again but this time as part of a small group while being observed by the interviewers. You'll later have another group case study. Good time management is vital. In fact to get brownie points volunteer to keep the time when the group is presenting at the end. Remember one thing. Don't concentrate too much on giving the right answer, since there usually isn't a unique right answer. It's how you give your answer that matters most - it's not the end but how you get there.
Lastly you'll have a final interview, which is nothing to worry about. They'll just try to find out how you think the day went and how you think you did.
Apart from that just keep you cool and you'll do fine. Hope you do well. I had to learn the hard way unfortunately.
