There is only one place to get the body manual.. That's from the factory that made it.. However this is the least important manual on the frame.
When it comes to the "Stuff" manuals, the converter, microwave, fridge, furnace, even the toilets.
Go to the device manufacturer's web site, Most of the folks who make stuff that goes into RV's have web support where you can download a PDF version of the manual.
Finally, if you want more there are a couple of books.. One is called the RV book... and as I recall the other is "The RV Owner's Handbook" (Might be mistaken there) Any RV store will have one or the other.. Camping world, of course, has the Woodall's one (One of them is a Woodalls)
They are "Generic" owner's manuals.. In places better than the factory manual in fact, Since they were written by RVers, not engineers.
Home is where I park it!