Paperspace blocks access from the Internet to your virtual machine's VNC port to protect your system from unauthorized access. If your system has a Public IP, however, you may wish to access the VNC console. To access your virtual machine with a VNC client of your choice (e.g., RealVNC, Chicken of the VNC, etc.), you can use ssh tunneling to forward a local port on your workstation to the virtual machine's VNC port. If you're using a Mac, a Linux workstation or Windows with Cygwin and OpenSSH installed, you can set up a tunnel in the following way:
ssh -L[local-port]:localhost:5900 [address-of-paperspace-vm]
ssh -L 5900:localhost:5900 18.104.22.168
If you're using Windows with PuTTY, you can find the port forwarding settings in the configuration dialog under settings -> ssh -> tunnels. For PuTTY, the local port will be any unused port on your local system (e.g., 5900 if you're not already using that for a local VNC server). For the destination, use localhost:5900.
Once the tunnel is set up, you can use the VNC client of your choice. Connect to localhost:[local-port] (e.g., localhost:5900), and your connection will be "tunneled" over the ssh session.