How can I add a external Domain?

If you add your domain as an external, you click on the "My Domains" then appears on "external domain" on the following page a command line where you select your domain and add you can add it. Before you create an external domain it must be taken at least one of the following precautions. This is to verify that you are the owner of the domain and is necessary for security.
As for your domain name server must be "ns1.easyname.eu" and "ns2.easyname.eu"

Otherwise there is the posibility to create a subdomain, which you will be told on the next page. This must be a CNAME record that points to "www.easyname.eu".