It seems I have missed something about the nostr protocol.

"Instead of requiring users to manually type new relay addresses (although this should also be supported), whenever someone you're following posts a server recommendation, the client should automatically add that to the list of relays it will query."

Does this mean if I follow someone that uses and posts on a public relay my client is not using, my client will automatically add that relay?

What exactly is a 'server recommendation'?