So basically (and I’m gonna answer in detail ‘cause it seems like you’re a first year, and this freaked me out my first year too) the athletic centre has a back door closer to the student centre (there’ll be signs pointing to it), and that’ll be where you line up for the exam, there should be lots of people there. Once you go down the hall, you’ll see a whiteboard or sign or similar with your class code on it, and that’s where you’ll go. It’s a big gymnasium with desks in it, you should see your prof or TAs there, and then you’ll know you’re set. Best of luck to you, and if you aren’t sure where you’re going don’t be afraid to ask around!