I was really nervous before, too. It ended up being pretty easy - they just took us in the office one by one (the other was in the hallway) and asked us a few questions about the other.
I think DH was more nervous that me because I went first and the lady spent 5-10 minutes just trying to get her printer working. :-P The questions were only a few minutes for each of us. As long as you know each other's full name, birthday, address, professions, and parent's names, you'll be fine. I can't even remember if they asked anything about our parents, tbh.
Good luck!