Hi! I also see a therapist in my university's counseling clinic. I started as a freshman and now I'm a junior.
When you go they will ask you why you're seeking therapy and ask you for some details on your symptoms as well as a bit of background info. In your first session, they will probably guide you a bit more, but in future sessions (in my experience at least) they will ask you what *you* want to focus on.
My best advice advice is to be as honest as possible. Your therapist can't help you if s/he doesn't know what's going on. It's really difficult and scary to make yourself vulnerable, but that's how the help and change happens.
Also, if you find that you and your therapist don't quite click, it's totally OK to switch to a different therapist. It's may feel weird or awkward but I promise it's not -- therapists are used to it and completely understand. Sometimes people just don't click well, it's human nature.
Good luck!