To kreate a new hosting:
1- Login to cpanel: http://www.mydomain.com/cpanel
2- Push the Add Domain button at Cpanel and write the web address that you want to add at the next page (without www). When you add it you will be asked to
provide an FTP username and password. Please make sure you store them for later use. When you finish the registration a new folder will be automatically kreated
under public_html directory for this new hosting. The files for your new hosting will be kept in it.
3- You can kreate email addresses for this new hosting at Email Accounts page on Cpanel.
4- Lastly you need to change the DNS of the newly added domain to the DNS of your main hosting domains.

After these operations you may need to wait until your new DNS to propagate through the internet. After the DNS are fully propagated you can access the FTP area
of your new hosting and upload your web site files.