Hey! Unfortunately the process for becoming the first lemm.ee subscriber to a community on another instance is a bit clunky as of Lemmy version 0.17.4 - but it should improve in the future!
For now, I can see that https://lemm.ee/c/aboringdystopia@mander.xyz has successfully synced and you can become a subscriber. If you want to become the first subscriber of any other external communities, check out the "How do I join a community from another instance?" section in our FAQ, specifically the "Option 2" section.
Note that the first search will always say "No results", but in the background Lemmy will kick off the sync and the results should appear in a minute or two!
If you have any trouble following those steps, let me know and I'll help you out!