Hey Jim, welcome to the forum. While we are camperless until the 19th, I have pulled three different types and lengths of trailers and driven a Class A. What I believe the dealer meant is you need to level the camper using boards, wedges, or whatever under the tires first. After you have it very close to level, then drop you stabilizers to steady it for use.
I carry some 2x8s (cheap) in two or three lengths that I can put down and back the trailer up on. You need to have a couple long enough to span both axles if it is tandem wheels. Stack them if needed, just be careful in case they flip or the tire falls off making them fly out and hurt someone.
It's easy, just have fun!
D_B Travelers - 30 nights in 2016... so far. 54 nights in 2015. 2014 Rockwood Windjammer 3001W Diamond Pkg, 2015 GMC 3500HD CC DRW Duramax, Equalizer 14K hitch, TST 507rv TPMS.
"Happiness? A good meal, a good cigar and a good woman - or a bad woman; it depends on how much happiness you can handle."
George Burns (1896 – 1996)