The manuals are usually very generic for the RV wiring, plumbing, etc. The rest of the manual is a collection of manufacturers manuals, and installation information. Get the model and serial numbers from the various components and get on Google to find the manuals.
I have never understood why people do not keep the manuals on the RV. That is where you are most likely to need them and then let them go when the RV is sold or traded.
Ken
Amateur Radio Operator.
2023 Cougar 22MLS, toted with a 2022, F150, 3.5L EcoBoost, Crewcab, Max Tow, FORMER Full Time RVer. Travel with a standard schnauzer and a Timneh African Gray parrot