How to use 1P to save a login previously saved only with Safari/Keychain

I have had 1P since 2011, haven't used it all that much in recent years, left the license mode for the subscription mode last week, purchased the Take Control of 1Password .pdf by Joe Kissel and am slowly making my way through it.
Following Joe's instructions (I think) in Safari > Settings > Autofill, I unchecked the box for Usernames and passwords.
With 1P unlocked, I input the Username and Password for a site at which I am registered.
According to Joe, 1P is supposed to recognize that this is a new site and offer to save the login information.
1P does not. After entering the Username/Password, I am logged straight into the site.
I strongly suspect it is some Setting in 1P that I have set incorrectly.
Can someone set me right on this?
Many thanks.

1Password Version: 7.9.4
Extension Version: 7.9.4
OS Version: macOS12.3.1