It is criminal that on a service called #Lemmy there wasn’t a community for #Lemmings. Then I noticed a server called lemmings.world and, obviously, had to create said community on that server.
I usually find searching for the URL and then searching for the community name works best on Lemmy. On Kbin searching for the address with the @ normally works first time - and clicking on the ! version ought to work too.
Normally I find myself typing the URL in, sometimes that finds it straight away, other times I need to search again afterwards with just the basic community name. Adding new communities in Lemmy is not very intuitive!