CNAME file in your repo informs GitHub that you're assigning a new custom domain name to your GitHub Pages site.
Next, we have to let the rest of the Internet know that we want to associate the custom domain name with your GitHub Pages site.
We can do this by creating DNS records, which are globally accessible records that map domain names to servers.
The DNS records are created inside of a Hosted Zone in Route 53. A Hosted Zone is essentially a group of DNS records for a single domain.