cPanel is your control panel to manage your site. Navigate to https://www.yoursite.com/cpanel (replace "yoursite.com" with your domain name).
So if my domain was paravelsolutions.com my cpanel would be located at www.paravelsolutions.com/cpanel
The username and password are the same as your main FTP login information. You can retrieve this information in your customer account area at http://www.paravelsolutions.com/customer/