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.
Test taken: None
Number of interviews: 2
Skype interview: no
Time between interviews: They were on the same day
Length of first interview: 40 minutes; Length of second interview: 40 minutes
In one of my interviews they were three interviewers, and in the other, only one. I was fairly
Mostly we just discussed sources: they presented a source, then asked me what I knew about it. After we'd discussed that they taught me a few further things of interest about that source. Two of the sources were historical extracts, and one was an archaeological find. It was just a bit of back-and-forth, where they could see what it might be like to teach me.
For the interview, you don't need practiced quotes or answers. If anything, that will take you out of a more helpful mindset.
Really listen to your interviewers, don't rush. Just think about the interview as a moment in time where you can learn something, and let them teach you.
Also, be really clear in your own mind about why you want to do this course. Not just in general about how good it is, but why you specifically want to do it.