I have no idea unfortunately - we’re all feeling our way here at the moment…

Ok, so I’ve just joined it. You have to search for it in the ‘All’ communities tab and subscribe there first. Then you can post. That advice you followed in the thread you linked to is wrong - they missed out a crucial step.

It’s a bit worse than that actually. I’m now seeing several communities with exactly the same name that originate on different servers - so clearly Lemmy doesn’t have a rule about duplication once you cross a server boundary. That’s going to get unwieldy quite fast particularly if, I dunno, “Aww” gets popular on two separate servers at the same time - I guess I’ll have to subscribe to both…