Are you applying for Capt or FO, and if FO whats your experience?
Not too sure if this is still the case but when I did it:
Day 1: Psych test, maths test, verbal reasoning and a group exercise.
Day 2: Personal interview which includes a presentation, used to be CFIT. Think it can be more B757 related if you're rated. The interview was quite long and in depth, but well natured.
Day3: Sim. As per the brief they send. No gothcha's. Again this probably increases in complexity if rated, DEC etc.
I'm not sure what you've been told. But will be for a Leipzig base. Seriously think about this. No direct flights from the UK, strong Euro.
Overall, I still enjoy the job, but morale is pretty low. Good luck!