Click the green Launch button next to Domains. This displays a list of your domains.
Click the domain name you want to update.
In the DNS Manager section, on the following screen, click Launch
Click the Add Record icon in the toolbar. The Add DNS Record window displays.
From the Record type list, select CNAME (Alias).
Complete the following fields:
Enter an Alias Name — For the Alias Name, enter only the subdomain of the address you want to use for your Unbounce custom Domain. For example, if you picked promos.mydomain.com as your address, enter promos here. Or, if you're using a root domain such as www.mydomain.com then you'll want to enter www here.
Points to Host Name — Enter unbouncepages.com here.
TTL — Select how long the server should cache the information.
Click Save Zone File, and then click OK to confirm the changes. The new CNAME record displays in the CNAME (Alias) section.