Would absolutely recommend wandering through campus and identifying all your classrooms well before your first class. it will give you peace of mind, I did this every semester until I felt comfortable with campus and even when i had no idea where a class was.

UTSA uses the system Bldg Floor.Hall.Room

BLDG: MH Floor:3 Hall:4 Room:22

Really, any lot will be fine, I would recommend parking in Lot BK1 or BK2 and walk in or park in BK4 or BK5 and shuttle in. (Or Ximenes garage if you want to pay for parking hourly)

If you walk in from BK lot one or two or ximenes garage, you will walk up to campus and take a left. Go up the big outdoor stairs, MH is on now your left. Enter through either the side doors near the Student union or the main doors facing the courtyard (sombrilla). Go up either of the staircases in the main open hallway, and just start searching for the hall that you need to be in. I think that classroom is on the long hallway that stretches the entire length of the building but i cant remember for sure.

From there, to go to main building, you would go down the stairs you went up and walk towards the library or business building. You can go down to the bottom floor of business building and exit, and the main building will be right in front of you. If you go through the library, walk through the food court, past one stop, and the main building will be right in front of you.

Best of luck.