RVs have light switches near entry door, with class A rigs there is normally a bank of them, they should be labeled but they could have worn off or faded. The switch that turns lights off as well as refrigerator is battery disconnect, leave that on and try each switch individually. Some are hard to identify as they are for steps, patio, and storage bay lights, hard to notice during the day or if you are not outside. One of these switches will be dedicated to your overhead lights, there should also be a secondary overhead light switch in bedroom area as well.
We have always had TTs, 5ers, and toyhaulers and the owners manuals provided by manufacturer were abysmally generic. Not sure if this is customary among builders of class A rigs, but the owner's manual provided by Monaco is around 350 pages, I have yet to read it all but it covered every interior switch in detail. I know it was quite a learning curve for us when we first got our class A, in due time we were able to figure everything out. Here's hoping you have as much fun as we are having, my DW was losing interest in the RV lifestyle, she is enjoying it now more than ever.
