3x 20 min interviews, 1 per day
Interviews 1 and 3: personal statement, general discussion; interview 2: written work
Make notes on personal statement and written work
Try not to overthink responses
Remember this advice isn't official. There is no guarantee it will reflect your experience because university applications can change between years. Check the official Cambridge and Oxford websites for more accurate information on this year's application format and the required tests.
Also, someone else's experience may not reflect your own. Most interviews are more like conversations than tests and like, any conversation, they are quite interactive.
Number of interviews: 3
Time between interviews: I had one on each of the three days I was there, so about a day between each
Length of interviews: Between 15-20 minutes
Online interview: No
My first interview was more focused on my personal statement and my personal experiences with history, before moving onto more general questions. My second interview focused on my written work, and was more like a debate whilst the first was conversation-like.
My third was again focused on my personal statement (it was at my current college not Brasenose) but this one focused on the intersection of history with my other subjects and briefly on my coursework.
I prepared by looking over my personal statement and writing notes on the parts I thought they'd ask about so I knew what to say if they did. I also went over my submitted written work and did the same thing. It really helped focus me and relax me as I knew what I would say to questions they might ask me.
I looked at the advice on different student websites, as well as looking at past and example papers to gather as much info about what the exams would be like
I would say not to panic or overthink your responses. Let your argument flow naturally and be prepared to defend your point if it's challenged by the interviewers - they like to do that. I'd also say that it's ok to change your point of view after a discussion.