I have done this before. I was really embarrassed about it. It turned out to not be so bad. How mine worked is you had to write down three positive things you did the day before and share. We would each bring a topic that we wanted to discuss. They teach DBT skills. You see a pdoc. For me it was to discuss getting on the meds I was denying I needed. Things like that. Now I hate large groups and had a great deal of anxiety in social settings. This was the hardest part. Very helpful overall, as much as I hate to admit this. I still use the skills I learned to this day. Try to relax. You will be fine. Just remember other people that are in there are struggling just like you.