the instructions on the completion page where it gives you a password should have also told you to go to your client's settings to set your NIP-05 ID. you'll need to do that to activate it.
Discussion
Hmm idk if I fully understand. I paid and put in my public key. Not sure what’s next
Once you are listed in the json on his domain you have to update your profile at a site like https://metadata.nostr.com (after installing nos2x extension) that links your account to the domain json for verification
You can look at domain.com/.well-known/nostr.json for your username to pub key mapping and then in NIP05 field you’d put username@domain.com (replace domain.com with nostrplebs.com I think it was in above)
Sorry, out with family for dinner. You can now add your NIP-05 ID to your client settings profile section. If you're using Damus, you may need to use another client that supports updating your NIP-05 ID such as https://astral.ninja or https://metadata.nostr.com.