When I started therapy I never went in with any sort of agenda. I was depressed so I generally just talked about how I felt throughout the week and my T guided me through her questions. As the depression lifted and we started talking about other things that had happened in my past or realizations I had had over the course of the last week, I began to have at least one thing that I wanted to talk about. Usually that one topic will take up the entire hour and will lead us toward something else. I think there was one session where I had two things I wanted to discuss so I changed the subject half way through after I didn't have anything else to say about the first thing.

I think a good therapist will help you come up with some stuff to talk about at first and will then guide the conversation to a place where they think some good stuff could come out. Another time my T asked me what I wanted to work on that week and I said I didn't know so she asked me about something she knew I was involved in and the conversation took off.

You can definitely come in with an agenda if you want or tell your T you need some help or guidance to get started. I'm not sure how long you've been in therapy but it is something that develops with time for some people.

A good place to start is what brought you to therapy in the first place and if that is still an issue for you.