There are 6 or 8 bolts at the bottom of your bumper that attach it the rest of the vehicle. There are also 2? brackets that attach your bumper to your fender?.
I know for sure there are those bolts at the bottom which are 10mm. I only know this because I hit a pine tree recently and immediately took off my bumper as it looks 30x better.
Oh, and I had no trouble with the airbag sensor. I was told they are the two yellow things(1 left, 1 on the right) and you shouldn't set them off by unbolting the bumper.