OK, so you went and bought a 40-foot (12-meter) motor home. How are you going to get it off the lot? Are you just planning to navigate and let someone else do all the driving? What if your driver gets drunk? Or sick? Or too tired to drive?
In general, it's a good idea if everyone on the trip can make right turns, left turns and park. Fortunately, RV driving schools are not hard to find. You can enter "RV driving school" into any search engine along with the name of your city, and you're sure to find an instructor nearby.
Are you in a pinch? There are a number of instructional DVDs out there, too. But if you go that route, be sure to pick up some orange cones, find a big parking lot and drag along a patient, experienced RV driver to get in a little practice before you hit the road.