As you noted, it is best to start with the TM manufacturer's site (
www.trailmanor.com). Look down through all the info on floor plans, specifications, and so forth. And the photos are really good.
Beyond that, this TrailManorOwners site is probably your best source, since it is dedicated specifically to TMs (not generic RVs or trailers), the info comes from actual owners, and the moderators filter out the kooks that you find on other sites.
There is a LOT of info here, and it will take you a LONG time to read it all. But dive in and have fun. You don't have to swallow it all in one gulp.
I would suggest that you scan down the list of articles in the TM Technical Reference Library (aka
TM Info You Won't Find Anywhere Else) and look at whatever catches your eye. The checklists are particularly useful for beginners, if only to acquaint you with some of the terminology and some of the concepts.
Then scan down the list of topics in the Tow Vehicles forum. You didn't mention what you plan to tow with, but that is an important consideration and you will find a lot of info here. New owners sometimes make expensive mistakes, and this area can prevent some of them.
The Prospective Owners forum has lots of good info for beginners.
And don't fail to ask any questions you have, no matter how simple they may seem. Lots of help is quickly available here.
Bill