Secure Shell (SSH) - sometimes called Secure Socket Shell - is a Linux protocol that you use to connect to the console of your gamed! VPS. SSH is the most common used protocol used by administrators to access their servers by remote and is the equivalent to the Windows Remote Desktop.
You should have a basic Linux knowledge if you want to administrate your VPS by hand because the whole administration happens over the Linux console. You can install any service that you want to like game servers, voice servers, FTP servers or Apache for your own website.
If you're afraid whether you can handle the SSH console administration then we recommend our gamed! Webinterface.
You can easily install several game servers for your VPS with it from within your browser.