How can I open federated links in my home instance?

I’m trying to find content on other instances (primarily communities but sometimes posts). Sometimes I have the @-handle, sometimes I have a URL. I want to open them in my instance in Mlem.

So far I’ve tried the standard search-for-the-URL trick which works for links on the web, but not at all in Mlem.

How do I get Mlem to open a link to a community or post in my active instance? Or, even better, in an arbitrary instance I have an account for?