Welcome and congrats on your GeoPro FBS19. Don't be nervous and take your time. There are two ways to learn, 1) make mistakes and 2) ask questions so you avoid making mistakes. Make double sure your tow vehicle can safely tow your loaded camper. Tow your camper to an unused parking lot and practice backing up. This time of year school parking lots are pretty empty. Read the manuals and understand how all systems operate. If you can use Camp Driveway the first couple nights to get used to things. Since you've tent camped you have a solid idea of certain needed items but trailers require a bit more. Don't buy a bunch of stuff you don't need.
At a minimum there are however some things that are necessities:
leveling boards or blocks
water pressure regulator
potable drinking water hose
inline water filter if your GeoPro doesn't have an onboard one
good quality dump hose
clear end attachment for above so you can see when water runs clear when dumping
disposable gloves for use when dumping
chemicals for black tank
check to see what fuses you have and bring extras
step rugs will help keep dirt/pebbles outside
sense of humor
Although not cheap I suggest an EMS unit to protect all your onboard electronics.
I'm sure I'm forgetting some things but this will give you a start. Plenty of you tube videos you can watch. https://www.bing.com/search?q=essent...FORM=QBRE&sp=1