Logging in to the cPanel control panel is very simple. In your web browser's URL bar, type one of the following URL's:
https://youripaddress:2083 (SSL secure)
You will need to substitute the main IP of your VPS for 'youripaddress' above. If you choose to log in using SSL encryption and have not yet configured an SSL certificate for your VPS signed by a trusted authority, you may need to opt to continue past any security warnings that may pop up, depening on how your web browser is configured.