Relays are the backbone of how Nostr works. It is how the notes you post get distributed around the network.

When you post a note, others will only see it if you are writing to a relay they are reading from. Likewise, you will only see what they post if you are reading from a relay they are writing to.

Looks like you are just using the default relays for Amethyst and that's probably fine to start with. Eventually you may want to add a paid relay or two. Just keep your relay list down to about 20 or less.