It was actually my second try of joining an instance and waiting for my approval was hard (it only took a couple of minutes, but that will turn off "average" users forever). I'm glad I made it!
Make sure in your settings that you choose Hot, Top 6 Hours or Scaled if you want to see a more refreshed timeline. It defaults to Active, which is ironically, less active for seeing new posts.
You have both a timeline for communities you're subscribed to, and an "all" timeline. The subscribed one definitely is better if you subscribe to a few communities and dont care about others, while browsing "all" gives you - well, all communities across all of Lemmy. I guess thats pretty similar zo reddit? Each timeline can be sorted individually. I might also suggest the "new comments" sort to see posts with active discussions going on in the comments.