Tip: If you previously created your Google Site through Google Domains, your site’s already connected.
Important: Before you connect your Google Site, make sure you use the same account for both Google Domains and Google Sites.
On your computer, go to Google Domains.
Click the domain name you want to manage.
Open the Menu .
Click Website Build website.
Under "Simple site," click Continue.
Click Use existing site.
Enter the subdomain you want to use.
Select the Google Site you want connected to your domain.
Click Connect site.