The first interview was a one-way video interview - all simple behavioral questions, why you want to be part of the program, etc. (4 questions total). Next came a 1-on-1 interview with the recruiter, who is the head of the program - also 4 behavioral questions and pretty easy. Last came the final interview day, which consisted of back-to-back 45-minute interviews with full-time employees. The interviewers were all focused on different types of questions (for me the 3 interviews were focused on your strengths and weaknesses, company fit, and communication skills, respectively), and I think the main goal is to see how well you fit the company culture / values. There was always time to chat with the interviewers after, so definitely be prepared with questions! I found that if they didn't ask specific questions on topics I wanted to bring up (i.e. my interest / fit with the company culture), I was still able to do this during the latter half of my interview with my own questions for the interviewers.
The interviews were overall really enjoyable and all the employees I spoke to were so easy to talk to and super nice! Also, the turnaround rate was ridiculously fast which I loved. They never left me for more than 3 days without a response after each round, which was super nice since you don't have to wait to find out if you're moving on to the next round!