I was in your same position when I became the Compliance Officer several years ago. Unfortunately for me, my ego got the best of me and I tried to "know it all" before they came in. I worked myself into quite a panic trying to read and understand EVERYTHING before they got there which is an impossible task in and of itself!
The best advice that was ever given to me was when an examiner comes in and asks you a question that you do not know the answer to don't hesitate to tell them that you will look into it and get back with them. Unfortunately this really intimidated me when they did this. You feel like you should have the answer to every compliance related question they ask because after all...you ARE the Compliance Officer right? But just remember too, that they sit in your conference room with a copy of the regulations out on the desk perusing through it as they perform the exam.
Look over the documentation/information requests and get familiar with the general requested information. This will give you a sense of what they will look at. Also, if you have access to past exams, go get them and review all past violations or recommendations because this will be one of the first things they will look at to see if you have corrected these past deficiencies.
Get with the department managers and explain that you are the liason between the FDIC and the bank but that you have to have their utmost support and cooperation during this time.
Good luck and we are always here to support you in a crunch when the time comes, if nothing else for moral support..just remember you can do this and once it's over you will be a seasoned vet!