New to TT's, what do I need?

Beer.

Some things on my must have list. Some basic tools like lug wrench, hot water heater drain plug wrench (or socket), phillips and flat screwdriver, zip ties, black tape, small bottle jack for changing tires if needed (spare tire), a small bottle of bleach (in case of funky water), tire pressure guage, blocking for leveling under tires and stabilizer jacks, 5gal water jug, flashlight, weather radio, black tank treatment, flyswatter. Be sure to check all your systems and maybe even camp in your driveway for a night or two to get the feel of things.

I would get a filter for your water that you put in your trailer when you are not at home. Make sure all of your appliances work properly. I always carry a barbque lighter for the stove and other old appliances. Check your LP hoses before you go out. Make sure you have the proper length stinky slinky. If you are going to use chemicals in the black water tank, make sure you have them. Check your spare tire and have a good jack and some tools. Always carry a couple of quality flashlights. Put grease on your ball before towing and get a rubber slip on cover for the ball so you don't get greasy when walking by it. Check your batteries for their condition.

Potable water hose, sewer dump hose are the top two. From there on a pressure treat 2X6 cut into about 14 inch lengths to use as leveleling blocks. A good bubble level to level with. Pots pans, dishes etc for cooking and eating. Bedding. A series of electrical adapters for 15 to probably 30 amp maybe a real heavy duty extension cord. From there youll figure it out as you go.
Personally since we use a lot of NF camp grounds we carry about 250 feet of water hose and a blue tote to dump the gray water. Plus a generator to suppliment my solar panels when necessary.