1. Now login your WHM panel here your enter your username root is common for all WHM panel and password (when you setup your server then he ask server name and password).
2. When you login your WHM panel then setup your WHM panel when you setup your panel now choose account function option.
3. Create new account fill your domain name , user name and password.
4. Now login your root directory like www.example.com/cpanel and press enter login dialog box come now fill username and password.
5. When you login your root directory now you choose addon domains option and add your all domain here if your domain is currently working on ohter server then you first chane NAMESERVER like ns1.example.com. Otherwise he show error message your domain run on another IP ADDRESS.