Good luck on your first outing. Be sure you get all your questions answered during the walk through!!! My first one lasted about 15 minutes and I was more confused when I left than when I arrived! Now I do them as a part time job in the summer and it takes at least 1 1/2 hours, sometimes much more.
As Jim says be sure to take your time on the walk through and ask questions. If the person doing the walk through can't answer a question to your satisfaction don't let him put it off insist he get the answer while the questions is still fresh in your mind. Above all DO NOT let them rush you if it takes a couple hours so be it. It is for your benefit to understand your new rig. Congratulations.