Step 1: Log in to Simple Control Panel. For more information as to how to do this see How do I access my Dedicated Server using Simple Control Panel?
Step 2: Click the Domains icon.
Step 3: Click the Edit button for the domain you want to add a subdomain to. If you are unsure which button is the Edit button, view the tool tips for each button by hovering your mouse cursor over the buttons to the right of the domain name.
Step 4: If there are no domain names listed, you need to add a domain before you can configure a subdomain for it. For more information, see Adding New Domains.
Step 5: In the Domain Configuration – Subdomain area, click Add Subdomain. For field definitions on any screen, click the help button.
Step 6: In the Server name field, type the name of the subdomain.