Sadly, you gotta use the other instance to find communities your into (or active there) and then add them by searching for community name on your instance.
Lemmy Support
Support / questions about Lemmy.
Until someone on your instance subscribes to a community on another instance, yours won't have any info about it. So it won't come up in search results.
You can run a search for a specific community if you know and enter it's exact name and instance. You might have to do the search twice. Once to tell your instance to look for it. A second time to see if it found it.
The place to find those specific community names and instances, is here
Thanks, this feels like a missing feature to me. The ability to scan for communities that are unknown to my instance while logged into it should be included with federation but I'm happy with the outside resources until that gets fixed
How would your instance show you things it doesn't know about?
Are you resting because you want to know, or are you asking because you don't think it's possible?
Both?
Well, the feature doesn't exist yet, so I can't answer your first question :) as for the second, history / chaining can be fetched, for example, lets say you receive a comment, and the parent commenter is from another instance. Or someone from a third instance comments on a post of a community you’re subscribed to. As long as that parent commenter is from an instance thats allowed (IE in the allowlist or open federation), it will pull it. Meaning the technology is already being used today, but hasn't yet been implemented for this particular feature.