@Raccoon It’s a lot like Mastodon. You pick a server (AKA “instance”) that has the kind of theme and rules you’re ok with. Here’s how you find an instance: https://join-lemmy.org/
Make an account and start joining communities on various other instances. Here’s how you find communities: https://lemmyverse.net/communities
@PunaisetPimpulat @Raccoon this is the way. And if you decide you want to be involved in a different instance, you can just sign up for another one or there are tools to migrate an existing account from one instance to another. I personally have a couple different accounts on different instances. You can switch through them seamlessly via the #liftoff app.