One in-person interview where you take a mechanical aptitude test and pattern recognition test administered by HR rep. Then interview with one or two of the mechanical engineers that you would be working with. It is a very relaxing environment.

TL:DR there were 2 interviews and a mechanical aptitude/tool test, whole process took about a month. I approached a recruiter at the career fair because I thought their presentation board with all the tools and gadgets looked cool. I sent a follow-up email to the recruiter the next day saying I enjoyed meeting. Two weeks later, I was contacted to do a phone interview. The phone interview was behavioral and pretty relaxed. The next week, I did a Microsoft Teams interview with two engineers, one of them being my manager. They wanted to hear a lot about my projects. The last step of the interview process was a 20 question test with some simple but deceptively tricky physics problems, and a 15 question tool-identification test. I got an offer about two weeks after that.