You will have lessons on Battlefield Casualty Drills and Team medic skills. These are the fast and dirty actions taken during operations immediately after an injury, in order to save the life of a casualty. Not overly complex. If you want to be a medic then join as one. We had CMTs attached. It is possible to become a RCMT but unsure how feasible that is these days.
From what I have read from first hand serving reserve CMT, the courses are nothing like regular CMT, I think it's a two week course, but I'd contact your AFCO and ask what qualifications you can get as a reserve CMT, that should give you a better insight,