I had an introduction call of around 30 minutes, basically going over the information from the job posting.
I then got two assesments to do, I had two weeks but finished within 2 days. You need a few hours to research their website but it's really do-able and easy to combine with even another full time job.
Then I had a 60min call with the head of Customer service and a sr recruiter. It was very relaxed, they asked some interesting and good questions, and were very happy to listen to my story.
Then I had another interview with the CHRO which was slightly more formal, but still in a very relaxed setting.