Hi I went to Ross Interview recently. It was very informal and they are there to review your application/essay/transcripts..speak to you about why you want to be a doctor? Will you adjust to a new lifestyle? What speciality do you want to enter? It was not too bad.
These questions that you are asked you probably already have an answer to by now* so just be yourself and honestly explain your point of views. That is my recommendations. Good luck. ps. what class are you applying for?