If your fiance is a smart man he won't give you lessons. Just take the truck and trailer out and drive around. With a goosneck trailer you will need to swing wide when turning because the trailer will cut the corner when you turn and if you don't allow enough space you'll run over the curb or hit whatever you're turning around.
This... terrified me at first but I hooked my trailer up and drove it around everywhere for a week. Trust me... pulling in and out of some of those parking lots in town is a pain, but you learn quick how to maneuver. You also learn to park at the back of the lot. Lots of exercise
. Basically if you park where few others go most places don't mind if you take up two, three or possibly ten spots.
For slowing and stopping... act like you have a load of eggs in the back. Take your foot off the gas pedal long before you put it on the brake. To go... slow and easy is the way.
Like kevinshorses said above... big wide turns, your gooseneck does not follow your truck tires. Once your trailer tires reach the turn point you're pretty safe. When coming up to a sharp right turn, put blinker on and go as far left as you safely can... not far enough though for some idiot who can't see blinkers thinks they can pull up beside you on the right.
Speaking of annoying drivers... understand that once you are a pulling a trailer just about everyone else thinks you are going too slow. Doesn't matter if you are going 70 they will still insist on passing, pulling out in front of you, or riding your tail.
As for backing up... find a empty parking lot and pretend the white lines are other trailers.