cPanel is the control panel of your hosting account.
From cPanel you can control many aspects of your hosting & it's features.
To login to your cPanel, go to http://yourdomain.com/cpanel
If you are behind a firewall and can't access the above link, try http://cpanel.yourdomain.com
For brand new accounts which are still waiting your domain name to propagate, you can access using your hosting IP address (see your signup email):
http://your-domain-ip-here:2082/
Your cPanel login details were sent to you in your hosting signup email.
If you require the password to be reset, contact support@primehost.com.au
Note: Changing your cPanel password, also changes your main FTP login password.