Hola former Redditor!
You can subscribe to any community that shows in your feed.
It may take a few hours to get accepted, since it does depend on the instance that community is hosted on. They are actually run by folks that may be off doing things at time so if no one is around to approve you right away, don't panic. They'll get there. I made the mistake of signing in on a ton of different instances, but am on old.lemmy.zip. Because of course it's got the old reddit layout, which allowed me to move in w/o missing a beat!
The only instance I haven't bothered with is the lemmy.ml since it can be a bit fractious (the rumor is they're "tankies" that is, pro Putin folks.. thanks, no.. that's okay, I'll pass..) and has a bit much drama - which I am SO over since I got permabanned on Reddit last October.. two weeks shy of 15 years.
The main thing I like is there is no running karma tally outside of what's directly on your comments or posts!
It's WAY more laid back and so few bots to passive-aggressively wind one up.