Congrat's and welcome. My advice for a first trip is keep it within and hour or less of your house. Some even do it in their driveway so you have access to everything and can't forget anything. If you do venture out then go to a full hook up facility that is close to good dept and or camping supply stores so that you can buy what you need. Those lists can get out of control and they never really go away. After the first night and morning you'll be surprised at just how much crap you really need, especially if you did not already transfer from another trailer.
Small check list before leaving your house.
Wood 2x8 planks for leveling, jack, power cord with any adapters that you have or need, flashlight, fuses that fit your TT and TV in the correct amps, chocks for your wheels and a sewer hose with connections and gloves. Safety equip like FireEx, jumper cables and other various key things.
Also since your unit is used change you battery in your smoke alarm, CO alarm and check the level of charge on the FireEx in the unit. Turn on your fridge at least a day ahead. Check water system for leaks and don't forget to fill the hot water tank before turning it on! Propane levels.
I'm sure I missed something critical but you will see others lists of must haves to compile a very good starter list. Good luck and enjoy it, you'll be a pro in no time.