Hello fellow Redditugee, I found Lemmy Explorer https://lemmyverse.net/communities to be very handy. I like the layout and the search/sort capability. The process I followed to subscribe to communities was to:
In Lemmy Explorer, click on the community@instance name (eg !maliciouscompliance), which automagically copies it to the clipboard.
Then in my home instance (aussie.zone) I clicked on the search icon (magnifying glass) and pasted the details into the search box.
I then click Next (not search).
The search will initially show “No Result” while it searched the Fediverse, but then the community will show up (I’m using dark mode so it shows up in green as a link).
I click on the link to open the community from my home instance and click on the subscribe button. Initially the community may be set to “Subscribe Pending” - I guess it needs to be reviewed. I’ve also managed to subscribe to Kbin magazines from Lemmy using this process. Note: this is on PC using Firefox