How to Install 3rd Party Files?

That’s correct. Install is on the default C: path and game files are on D:
Community folder is:
C:\Users\YourUsername\AppData\Local\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalCache\Packages\Community

Am I right in assuming the Community folder is only for holding community mods?

I must have write privileges to that folder, because not only was I able to extract to that folder, I was able to write SOME files from inside the mod’s folder to the Community folder. Just not all of them.

No internet restrictions I’m aware of.