DNS records added via the DNS Manager section of the Control Panel take effect only when the domain name uses the DNS service of your hosting account.
To add a CNAME record, you should:
Go to the DNS Manager section.
Click on the Create button to the right of the interface.
Fill in the following fields:
Subdomain: Type the name here (e.g., "www" for www.example.com). Leave blank for example.com. Domain: You can choose to apply the changes to one or more domain names through the Domain selector. Type: Choose CNAME from the drop-down menu. Target: Enter the hostname for the CNAME record. TTL: This is the time-to-live value of the record. The default is 14400 seconds. We would recommend leaving the default in most cases.
After applying all values, click on the Submit button.