oauth2 with GMail?

[Grant Edwards]

I'm trying to figure out how to use oauth2 for SMTP/IMAP (mostly SMTP)
with Gmail by following the instructions at

   https://luxing.im/mutt-integration-with-gmail-using-oauth/

But, I get stuck when I get to the rather vague part of the
instructions that say to go to https://console.cloud.google.com/apis/credentials,
create a project and download credentials.

Google seems to require I that pre-register my project's domain (which
I don't have) in order to generate credentials. Am I doing something
wrong?

I'm also not sure what the instruction "if this page says anything API
not enabled, enable it" is supposed to mean.

--
Grant