To have multiple domains(more than one unique website) in a single account, first thing you have to do is to purchase the addon slot and domain from your customerarea. After purchasing the addon slot and the domain, login to the cpanel and the option 'Addon Domains' will help you to add the domain to your account.
If you don't want to have saperate websites, but a saperate domain name which loads the same website, choose the option 'Parked Domains' in the Cpanel.Here you can point the new domain to the primary one.
