Therapy

First off I want to say I am not wanting personal details or you to feel that I am invading in your privacy. I have recently started going to therapy sessions. I have never done this before and am not sure what to talk about. My therapist said I have to have the topics we speak about in my next session. I am a very shut down and am not sure how to bring up or talk about things. If you are in or have been to therapy what are some general topics you talked about.