Welcome to the forum. There are a few of us Challenger owners here so if you have any questions feel free to ask. When asking a question some of us have different floor plans so the answer provided may not match our experience to a T but we'll get you close.
Do you know if the dealer applied the step recall to your coach before you took delivery?
Also, after giving the dealer time to register your warranty with Thor, call or email Thor warranty support and ask them to send you the following
12VDC electrical diagram
120VAC electrical diagram
Waster water diagram
Fresh water diagram
And if not provided by the dealer the build sheet which lists all of the coach components (e.g. AC, Conv/micro, refrig etc...) and the serial number of the component installed on your particular coach.
Again, welcome to the forum and happy travels.
US Army (Ret)
2015 Thor Challenger 37ND
FMCA - F432054