New here: how do I see posts from other lemmys?

I'm new here. I came over because I'm annoyed at reddit, but I don't quite understand how things are supposed to work.

As I understand it, Lemmy is like a reddit where a bunch of individuals run separate servers. My main interest is in /c/parenting.

I see that Lemmy.world's /c/parenting has some posts. Lemmy.one has some. Lemmy.can has some, etc.

None of these sites individually has enough posts/people to be useful (network effect), but together, they could make up a useful forum.

How do I get all of the other lemmys' /c/parenting posts to appear alongside the ones from Lemmy.world in the web interface?