yes, what utopian said, except that formal registration comes about a month before the UMAT test. Applications closed at the end of June this year, UMAT was end of July, and interviews were during the school holidays before the HSC.
Yep, thats bout all you need to know. One important thing though...do NOT underestimate the importance of the UMAT test. In the end it has EQUAL weightage to the UAI. So if you really want to get into med at UNSW my advice would be to prepare as much as possible (it is a natural ability test mainly) for it. There are prepartion courses that might help.