The useful starting point
A domain connection needs both a site setting and correct DNS records.
Start with the right information
Register the domain through a registrar you control. Keep access to its account and check which hosting plan enables a custom domain for the project.
Put it into practice
Enter the domain in the site manager and follow the displayed DNS instructions. Change the records at the domain provider rather than inside generated HTML.
Check before you share
Allow the configuration to be checked and inspect HTTPS at the public address. A saved domain field alone does not establish ownership or provision a certificate.
Original guidance for this installation. Connected services, available formats and prices are shown in the workspace before you use them.