How do I use VNC?

Start a vnc-server on the machine you want to control, with vncserver :1 (:1 means display 1). You will be asked to define a password for accessing your server and another one for just observing without interacting. After that, your server is up and running and you can connect to it with any available VNC-clients (e.g. TightVNC) by entering the hostname you want to connect to, like hostname:1.