New phone. Same nostr?

I love the idea of nostr as twitter without censorship. But right now it is not yet useful nor usable. With time it could be. But not yet even close.

First, I had only #[0]​ in my timeline, even though I follow 20 people. Then I joined some additional relays and now others are back in my timeline. I don’t understand what relays are nor why I need to join them manually. Why do these connections not happen automatically?

What are relays? How many should I connect?

Anybody out there?