Adding a Subdomain
From Acenet Knowledgebase
This demo will show you how to add a subdomain through your cPanel. A subdomain is a domain that is part of a main domain. For example, "mail.example.com" or "shop.example.com" are subdomains of the "example.com" domain. Subdomains have their own document root folders with their own content.
[1] Click on the "Subdomains" icon within the "Domains" section of your cPanel
[2] Select the domain from the domain drop down that you would like to add the subdomain onto
[3] Enter the name of the subdomain into the "Subdomain" field
[4] cPanel will automatically choose a document root for you (It is usually best to keep this the way cPanel sets it unless you have special requirements)
[5] Click the "Create" button to create the subdomain