There's an Aussie instance (correct term?) called Aussie.zone. It's pretty friendly and has some city specific subs (magazines? I'm struggling with fediverse lingo) as well.
Ha yea, I wouldn’t worry too much about the lingo, as it’s not really sorted out or consistent.
Instance/server - a fediverse place where you need an account to post but can see other stuff from other places if they talk to Escher through federation
Community/group/magazine - basically like a subreddit, but can look more simple than that on other instances that are set up to do microblogging like Twitter.
Lemmy calls them communities (good name IMO), kbin (similar to lemmy) calls them magazines (fun but different) and the generic more technical name would be “group”.