@DJDarren Lemmy communities seem to be treated like users on the Mastodon side of things, so you can just input @ username @ domain (minus the spaces) into Mastodon's search bar and follow them like normal. The posts then get boosted into my feed where I can reply to them like any other Mastodon post. There does seem to be a warm-up period if you happen to be the first person on your Mastodon instance to follow a community, but once that's done I've found the interop to be reliable.