Anatomy Scan

I have my 21wk anatomy scan scheduled for tomorrow morning!! As a FTM I have no idea what to expect and am pretty anxious. I’ve only had one somewhat in depth scan at 8wks where they measured baby and checked for a heartbeat. What should I be expecting? Will in just be an abdominal ultrasound or should I be expecting a transvaginal as well? Also, what questions should I be asking during this scan? Will they tell me everything I need to know or is there some information I have to do some asking for? Thanks in advance!!