On activation of your hosting account, you'll get your unique login information.
Once logged in, you'll see the default domain name on the account.
To add additional domain names, follow the steps below.
Step 1: Change the domain nameserver to the one contained inside your account activation email.
Step 2: Login to the control panel and click on Add Web Domain.

Step 3: Fill in the domain name, tick dns support and mail support.

Make sure to tick "DNS support"
Also tick "Mail support" if you will be using webmail for the domain.
Step 4: Click SAVE on the top right side of the page.

Congratulations, you've successfully added a new domain to your hosting account.