Hi Emma - with my first pregnancy I was just like you - i didn't know what i had to do. I just went along to my first ob appointment and he did all of those things that Janno said. He also did a dating scan. I had no birth plan, haven't had one in either pregnancy and won't have one this time around either. I am happy to go with the flow, and i trust my ob to keep me and my baby safe.
I hope your appointment goes well.