They are not exams, so no you do not need to have a camera on. It is not really possible to cheat because there is no "correct" correct answer, and the questions are subjective in order to decide whether or not you would make a good vet student and subsequent veterinary surgeon. It is inadvisable to try to cheat or collude with other applicants when doing these, especially because they are assessing your professionalism. In addition, veterinary schools have been known to frequent this forum and read the posts here.
The nature of the SAQ and SJT is dependent on which university it is for - information can be found on the admissions process pages on the university website.
Ideally, your work experience will have helped to prepare you for these, and they're not really something you can study for, as they are testing your professional nature. I would recommend being familiar with the RCVS code of professional conduct, but otherwise you cannot really prepare for the SJT. The SAQ will likely be more about you and what you have learnt about the profession so far and why you would make a good vet.