Just imagine you are sitting in a plane, a train or somewhere in the city and you'd like to do something on your computer. Often there is not many space to put out your laptop and start working. So wouldn't it be great to see everything that's on your desktop through your VR glasses? Just run the laptop, put it to the side and start working with your glasses and e.g. a Bluetooth keypad and mouse. With Cardboard VNC (VNC = Virtual Network Computing) you can do that. You just need the app and a program for your computer to run the VNC server.
Set up the VNC Server at your computer
Download and install RealVNC (you just need to install the server - you don't need the viewer). After installing it follow the link to the website to get your free key - there you have 3 choices - take the third one, which say "free license only, without premium features". Copy your license key and finish the installation (just follow the steps). After installing it, start the server.
Set up the VNC Viewer at your phone
Download and start Cardboard VNC Free. Click on the button "+" in the bottom right to add a new server.
Just enter any name you want in the first field. In the second field enter the IP, you can see at your server followed by a ":" and the port (default is 5900).
If you set a password during the installation of your server enter it in the next field.
When viewing your desktop with your VR glasses you can choose between two modes - you can control the cursor with your looks and the magnet button of your cardboard (if you have one) or you can just control it like you are used to with a mouse. I prefer the second mode but just try it out. If you want the second mode just check "Viewer Mode". Click "save" in the top right, start the viewer by clicking on its name and put your phone into your glasses.