I don't even remember man this was 5 years ago. You apply and then they offer your acceptance or whatever to come "interview" at visiting weekend but that was a joke and they're more just trying to rope you into doing 5+ years of cheap-as-dirt labor for them so unless you're totally incompetent you'll probably be fine and even if you're totally incompetent but reasonably teachable (ie: me) then you'll still be fine. They just want you there to work for them for cheap cheap cheap

First, zoom interviews - you basically chat with people about your research + future interests; will be asked about certain technical questions / experiment analysis techniques. Then onsite visits with 6 rounds interviews - the questions vary based on the professors, some are just casual chats and some ask stressful questions.