2x interviews.
Interview 1: problem solving, personal statement; Interview 2: personal statement.
Read over personal statement and texts included; mental relaxation; speaking to past students.
Be yourself.
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
Time between interviews: around 2 to five minutes
Length of interviews: about thirty minutes each
Online interview: No
For my faculty interview, I had to solve a small problem, which the interviewers talked through with me. For both interviews we talked in detail through my personal statement and my previous experiences.
I read over the books I'd mentioned in my personal statement as well as memorising other details from it. Then I did some mental relaxation before the exam so my mind felt clearer.
To be yourself! There's the false archetype of the "Oxbridge student" but your interviewers will be able to tell if you're not being genuine.