To me it seems like you guys at JRiver are proud of your 'secret knowledge'.
I get your frustration, but, that's unfair, uncalled for, and unnecessary.
Consider these things:
The JRiver team is small.
The software is, let's be honest, even for first time purchasers, not expensive, and for upgraders? a no brainer. Bear this in mind...
MC development moves fast. Maybe not as fast now as in years gone by, but it's still, constantly evolving. I've been using it more than twenty years, and still learn things new to this day. Attempting to document a user manual in this environment would require full-time staff for the output, and, internally, would require time whilst changes were conveyed from those responsible for the changes to those responsible for manual.
The manual? Honestly, How? It started back at V9.0.0.1 ~2003, with Media Jukebox preceding it way further back than that. If someone presented me with that manual, I would never, ever read it. I would come here and ask the question, get my answer, and be happy. I have a .chm help file here (thanks Lisa) that'll give you plenty of reading and cover you up to circa v12... Would you like me to share that with you?
I know that not everyone gets an answer, which is another thing aligned with your quoted comment....
Nothing is a secret. It's all here, on the internet, publicly available to all. The user just needs to craft their searches to zoom in on their area of interest and then, the chances of answers are high... If you don't get an answer, it's because no-one knows, not because we all know but prefer to keep it secret.
JRiver Media Center has immense scope. It will fit a vast number of different usage scenarios. Whether your focus is on asset management or playback, or both. Big software companies, think the likes of Adobe, Apple, Microsoft, off the top of my head, are regularly called out because they dictate to the user, who has generally paid a high price for a seat, how they must use their new software. Good luck interacting with
their CEO's about that. You got a problem with Windows, what do you do, read the manual or head for Google?
JRiver gives you the choice. It can feel strange to begin with. We are worried, nervous to move away from the given defaults in case we break something. You won't break anything. The MC 'playing field' is enormous. Over time, you can mould it to fit your space, such that it continues to work flawlessly, and you are so far removed from 'default' you can't remember what 'default' was... Then all you care about is that you never lose the setup you have, and then you learn that the software has your back, and you learn how and why, and you will never lose it.
Some of us, as we 'get it', hang around, grateful for the non-JRiver people who helped us get started, and find that we can, in turn, help others, and is so often the case, we learn more from the assistance we offer.
We're not a secret society. We ask for nothing in return, though the occasional "Thank you" is always appreciated.
It's not often I put my JRiver 'fanboy' hat on, and I totally appreciate that English might not be your primary language, but your quoted line annoyed me a little, and I have been, for other computer related reasons, really, quite grumpy this week... So you get the above to read

-marko