Step 1: online programming challenge. You receive 7 days to complete it after starting the challenge, essentially giving you unlimited time.
Step 2: 90 minute live coding interview. Unlike most live coding interviews, you get a period of time to code to yourself. You have to complete two simple questions, then you're supposed to get as far as you can through a tougher multi-part coding challenge. At the end of that period, you present the results of your code and walk the interviewer through what you've written.
Step 3: two hours of final-round interviews. These are officially two hour-long interviews, but they felt more like four 30-minute interviews. The first two sections each present one question on algorithms. The next 30 minutes is a behavioral interview, talking mostly about your experiences. The final section presented a class modelling question.
After each interview, you get time to ask your interviewer questions. I felt that everyone I talked to in this process was very friendly and supportive.