Hey,
Unfortunately we are not allowed to give out details as they have asked it to be confidential. Don't wanna risk my application.
Although it is pretty straightforward as long as you're confident and realistically prepared( Don't go overboard with this, you'll only stress yourself out)
There is the re take of the online tests which is just to verify your results, then there is the knowledge test which is pretty easy if you've studied the stuff sent to you. You don't need to learn any extra content at all!
As for the interview, prepare for it as you would for any past experience-scenario based interview. Keep the STAR method in mind. Can't really give out anything more.
As for the group activity, all I can advice is to just be yourself and be confident.
Hope this helps