I kept hoping someone else would put together a guide like this, and no one was stepping up. In the immortal words of Hermes Conradís grandmother*, if you want a box hurled into the sun, you got to do it yourself. So hereís my effort to fling this container at the sun. (Hopefully it doesnít contain our own universe.)
Along with a brief setup guide for Weland, it goes over some of the biggest pitfalls with modern mapping, some advanced techniques, and some weird quirks of the engine that I donít think have been formally documented anywhere else (and almost certainly not publicly). It also has links to numerous other resources, including the editors themselves, the Forge and Anvil manuals, the Forge tutorials, Hasturís Workshop, and more.
If you notice any errors/omissions, let me know. (Iím already planning to add sections on music and on Weland shortcuts.) Iíll see your responses a lot faster on Discord, but Iíll try to remember to check this place. I also canít promise to troubleshoot all your Weland setup problems (for one thing, Iím not its developer and only have experience running it on Mac and Windows); thatís what Discord is for. :P But hopefully this will help.
*God rest her zombie bones.