It was pretty chill. I got all 7 interviewers I had selected. There are different styles for each interview but bottom-line, be ready to talk about you've done in the past, know PIs' research before going in for the interview, some people ask technical questions especially if you're theory focused. Talking to the student hosts is the best way of getting to know the program and the culture in the cohort.
First day at CNS; second day at the medical school. Intro to the program and each subdivision; poster sessions by students; presentation by PIs.
It was like this before the pandemic, so I'm not sure how it'll look this year.
Hope this helps