2x interview; MAT
Interview 1: discussion of pre-reading, logic questions; Interview 2: textbook questions
Wider reading based on personal statement
Try to read some academic texts to get used to the format.
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: 2
Time between interviews: 10 minutes
Length of interviews: 30 minutes
Online interview: Yes
The philosophy interview consisted of responding to questions relevant to the pre-reading I had been sent beforehand. Then, I was asked a couple formal logic questions.
For maths, they had me answer some maths questions (one of which felt like a textbook-question) and the other which was more abstract (with guidance from the tutor). The atmosphere for the maths interview was pretty relaxed. They gave me hints for the abstract question, and asked me why I was using specific formulae.
I did some reading about the topics I raised in my personal statement, and revised maths units from my high-school course for that interview.
Past papers, which are listed on the website.
I think I would try reading some academic texts for philosophy to get a feel for the language - I found it rather confusing .