1. Grab the DNS nameservers from your hosting company. Enter them for the domain in your domain provider.
2. For WP Engine, there aren’t nameservers. Instead, grab the IP address and add for the A records www, @, and *. No change for MX or Cname or other unless you are moving email as well.
3. Also for WP Engine, use the big blue button on the right Add Domain to add the new address. Set as primary. Then add a redirect from either the www. version or the non-www version, depending which one is primary.
3. When the new url successfuly redirects to your dev homepage, the domain has propogated. Now in the wp backend, change your home and site url. This is done under Settings > General. This will make sure your domain stays there when it’s visited. But if you do it right away, you’ll get kicked out because your DNS is still propagating.