The interview itself lasts about 30min (more or less) and I took it with other candidates via Skype/Zoom. The overall process of getting the job and getting to the interview last about 2 weeks, from contacting them to organizing the interview to doing a demo class (which is a trial class where you show them what you can do).
The interview is extremely easy, at least in my experience, because you will probably be interviewed along side 2 or more other people. I have had 2 interviews for Acadsoc and both times with 3 other people who could barely pronounce and speak English properly, let alone fluently. This will already give you an advantage (if you really know English and how to teach it). I had two interviews because the first time they told me I was not accepted, and here's why.
Basically the most important part of the interview is when they ask you about your technological capabilities. The company does not care how well you can speak English, how much experience you have, or how much you actually know about English. They only care that you can deliver classes with a headset/earphones, good internet, and stable surroundings and background. Now I failed the first time only because I was not sure if I could have wired internet, even though my internet speed was faster than all the other candidates combined.
My main tips are that you are cheerful and communicative, and above all, that you tell them you can have wired internet and earphones at least. In the end wired internet is not a necessity and I always used wifi and had 0 issues.