Oh right, missed that you're specifically using Nostr SDK, so I'm not much use to you. Apologies.
Relay lists: kind 10002 https://nips.nostr.com/65
Follow list: kind 3 https://nips.nostr.com/2
To follow a new user I would imagine you append to and rebroadcast your follow list, but am not 100% sure on this.
Oh right, missed that you're specifically using Nostr SDK, so I'm not much use to you. Apologies.
