Searching it is the most likely option, since it’s a lot easier to find an instance if someone else on the same instance has subscribed, and it syncs over.

If someone hasn’t, you need to pop an exclamation mark on the front, so it actually checks the other instances, instead of just what’s synced to your local instance, and if you’re not familiar with that little tidbit (that’s not on any of the search screens), it would seem like it doesn’t exist.