Once you have signed up, the next step would be to configure DNS.
To use the American Cloud DNS service, which provides better integration as most records would be automatically created, simply create the following records at your registrar:
ns1.wp2tdsc0-0.americancloud.com -> 45.39.56.5
ns2.wp2tdsc0-1.americancloud.com -> 45.39.56.6
Note: The registrar is where you purchased the domain.
These nameservers are shown in the WordPress management interface:
You can also use your own nameservers, for example, CloudFlare. You will need to create the A record:
example.com -> 45.39.56.5
www.example.com CNAME example.com
Once you have configured the nameservers, the site will usually start resolving within a couple of minutes.