Matt Nash on Nostr: Dumb question time again! So I just downloaded this app from the app store and it ...

Dumb question time again! So I just downloaded this app from the app store and it just work's. I can send and receive note's which is cool

Now am I using someone else's node or relay to do this?

Should I be setting up something else to further decentralise Nostr?

I mean I've heard that when you use someone else's node to send bitcoin you are giving away ip adress etc. Is this the same?