Good advice from @coffeeat3 ! I’d add that if it’s zoom, pay attention to how they want you to interact. They may ask you to raise your hand or put questions in chat. Keep your camera on!
My guess is that this is not meant to be evaluative but a way for you to get to know more about the school.
Since you will be talking to students, this is a chance to ask about how they experience the school. What do do you want to know more about?
How they met their friends? What their favorite weekends are? How much they use student help centers vs help from teachers? Where they study? How much day and boarding students mix? If it’s harder to fit in if you weren’t there through 8th?
When we were applying (10 years ago), George invited applicants to a theater event with a reception, and there were tons of students to talk with. Nobody kept track of who talked to whom or what was asked. It was one of the things that really tipped the scale in favor of the school for our family – super friendly, well-spoken, down to earth kids – and a school that had enough confidence in them to not feel the need to “manage” them in this situation. Try to enjoy this!