Needless to say, the relevant knowledge, first of all, you have to look through the books, find the answers to the parts you didn't answer well in the written test, and maybe ask questions again. I didn't make this preparation at that time, so I was very depressed during the interview ... In fact, the professional knowledge you asked is not very difficult, but it is the most basic, but I don't know what the position you are applying for will be like. I suggest you go to their website to have a good look at the company size, service support and corporate culture. The more you know, the more you have to say. Finally, I will ask you if you have any questions. You should also grasp the scale and ask some appropriate questions you want to know, that's all.
Although it is a video interview, it also tests the quality of the candidates. It is necessary to dress formally and answer questions gracefully and appropriately. But the advantage is that you can do some preparations that can also be used in the interview process, and you can watch and talk at the same time. After all, you adjust the lens angle, and the other person's perspective is limited (the other person can see you during the interview, but you can't see the other person). In a word, we should be fully prepared.
I wish you a successful interview!