Meanwhile, for completely unrelated reasons, I decided to mention that the https://lemmy.dbzer0.com/ instance is run by the former top mod of /r/piracy.
I'm not familiar with how Lemmy does it, I'm a kbin user myself, but I believe it should be similar between the two. You subscribe on a community-by-community basis, so for example you'd put "piracy@lemmy.dbzer0.com" into the community search and then subscribe to it when it showed up in the results.
You are not logged in. However you can subscribe from another Fediverse account, for example Lemmy or Mastodon. To do this, paste the following into the search field of your instance: !piracy@lemmy.dbzer0.com