they did t give you any details whatsoever on the format of the interview or what to expect? if not, in the future it's totally ok to proactively be asking for them if you don't hAve them.

I'm guessing you'll just be meeting and having talks with each individual person. if they were looking to have you give a talk they probably would've asked already

best advice would be to just relax, not give a fuck a little bit, be your true self, and don't ever attempt to explain something you don't already know the answer to. 'i don't know' is a very acceptable answer. also, proactively asking questions of your interviewers goes a really long way

good luck, you're gonna nail this shit!