FIrst I had a skype interview with the what would be my boss. He also asked technical questions. Then I had a skype interview with two people working on the same group. After that they asked me to perform a technical task at home, for which I had a week of time. The task was a bit lengthy but it took me only 1 days and a half. Finally I had a site interview, during which I had 4 1:1 interview and I had the chance to discuss my solution to the technical task.