Three separate interviews which seems excessive but they are all basically the same questions - so just to make sure you get a fair chance. My experience was over a week and you only get invited to the next if you pass the current. My offer was made shortly after my third interview.

First stage is uplaod cv. The second involves online testing with math and question section. In math section its better to answer more and potentially get some wrong rather than perfect it. They are testing your ability to answer under pressure making educated guesses. Final stage is 3 online 1-2-1 interviews.