As far as I understand it, the toggles mean from left to right : appears on your home feed, receive messages from, I'm actually not sure what the people one does, appears in global, Searches.

So for instance the relay that I'm showing below I have set for everything because that's my own relay but on noster.band for instance I only have search enabled. And beyond my own relay, the only thing that I have showing in my global is the welcome.noster.wine relay.