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.

I think you're wildly overestimating that timetable - over on that site I'm a member of a sub where you need intimate knowledge of the subject to moderate it effectively (and because of the nature of the subject it gets a lot of trolls to put it mildly). With no community mods that sub would become a cesspit within days, as would subs that are currently the focus of the alt-right, such as science, LGBT subs etc. It's going to be a bin fire if the community mods leave - you'll feel so dirty you'll have to take a shower after every visit to your previously favourite subs...

So I think I've spotted a problem with how Lemmy's federation actually works. I can give you several examples, but I've spotted that there are several 'Technology' communities that originate on different servers. They're definitely different 'communities' because they have quite dissimilar subscriber numbers. That's potentially going to cause a lot of confusion going forward - I really don't want to have to subscribe to two or three of everything...