Pre-op
I assume it's the hospital preop? If so, you check in, the nurse verifies all your information, then you see the anethesiologist (dunno if I spelled that one right lol), then you give a few vials of blood, then it's off to do some tests if needed (I had an EKG and a chest x-ray). The whole thing takes a few hours to an entire day depending on how busy they are and how many tests are required. I suggest bringing a good book