There are several options for Windows VNC clients that you can find on the internet. Downloads of the Real VNC Viewer are available on the RealVNC website.
Once your PBS script has started, and you know your desktop and port number, and you have opened the tunnel to the compute node that is running your VNC desktop, it is time to start the VNC Viewer. Double-click on it, and it will present you with a screen to enter the hostname for your VNC server. VNC Viewer wants the server name and port separated by a colon, as shown here.
If the tunnel is properly set up, you will then get a password dialog; this is asking for the VNC password you set with
vncpasswd when you set this up.
The resulting desktop should look something like this.