@NobleWolf Did you see your universe name above the document list? It should look like this:
When you click that universe dropdown on the documents, it should only list universes that you have documents in; I'd double check your universe is listed there (and double check your document is in that universe). I can take a look if it is in that universe and you're still not seeing it, though!
Yes, I checked and the documents page looks like that one. But they're still not appearing on the Universe page, unless I add them manually somehow? I haven't been here in a while, sorry.
Oh @NobleWolf, I see what you mean – my misunderstanding. Documents added to a universe should show up on that universe's page automatically; you don't need to add them manually. The only caveat is that they'll only show up if the person seeing the page can also see the document: for example, if you're looking at your own universe you should always see its documents, but someone else looking at your universe won't see any documents that aren't shared publicly.
I just took a look and it looks like there's a bug somewhere that's keeping some documents from showing up on universe pages. I'll dive in and get it sorted out; thanks for letting me know!
Edit: should be fixed now! :)
I see them now, thank you!