The interview was pretty straightforward - she just asked to see bunch of papers , like taxes, payment stubs, joint bank account (or if you don't have it bunch of utility bills in separate names but at same address should be fine) and pictures ( we brought about 30-40 pics) . Just make sure you have all the required documentation and you should be fine (don't forget to do your medical)
Also they were very punctual - our interview was scheduled at 10:55 and we were called at 10:50 to go to upper floor . We did wait for about 30 mins after that and then on to the interview.
Good luck!