Quick answer: in the control panel open Websites, select your website, open Domains and add the domain or subdomain. Then make sure its DNS points to your hosting.
Add a domain
- Open Websites and select your website.
- Open the Domains tab and add the domain.
- Point the domain to your hosting: set the nameservers to dns1.cloudzex.com and dns2.cloudzex.com, or add an A record to your server's IP.
Subdomains
A subdomain like blog.yourdomain.com is added the same way. If your DNS is hosted elsewhere, add an A record for blog pointing to your server's IP. Free SSL is issued automatically once the name points to your hosting.