Hi!
I think you did it right :) But the way Lemmy is designed, it doesn't copy over historic posts and comments before you subscribed. I had a look at the community over at dormi.zone and there has been only one post since you subscribed, and that one you see here on Lemmy.today. But you won't see the older ones. New ones will pop up here though.
It's a bit confusing, all of this, in the beginning. :)
Make sure to subscribe to lots of communities since only a few has lots of content, and it can feel like Lemmy is a wasteland otherwise.
Me too, it's fun with technology that isn't owned by big tech. :)