Google Sites: Sign in...
Click "blake".
Give it a Title/Name and upload logo.
Settings: Custom domains
Click <Start setup>.
seostuff123.com <Next>
Message:
"Your domain is already connected to a different site. If you set up www.seostuff123.com to go to this site, it will disconnect from the existing site."
Oh.
.....
<Cancel>
<Backspace> <Backspace>
3-Dot Menu -> Remove
"Move to trash?" -> <MOVE TO TRASH>
Click on existing site.
Click "Pages".
Hover cursor over home page icon.
Click 3-Dot menu.
Click "Add subpage".
Name page...