This a simple 'Hello World' multiple LEDs blinking application to show nanoFramework is running on the smallest of boards. The Electron board is less than 20*20 mm.
Once you have Visual Studio 2017 started (I've used preview 3, but the latest Visual Studio 2017 will work too) you'll have to get the nanoFramework extension. Once this has been completed (requires a closed and re-opening of Visual Studio), you start a new project and select nanoFramework Application. Thereafter you have to add in this case the package to give GPIO a go. To accomplish this you have to right click the solution/project and select to manage the packages. Select to include for pre-releases, filter by nanoFramework, select the GPIO package and install it of course.
In order to view the nanoFramework devices make sure that you have chosen to see the Device Explorer window in the view other windows menu. Once you connect a proper nanoFramework device it will be listed here. After selecting the device you can view the details in the output window if Visual Studio.
Now you can try to enter code and try to deploy, and if all goes well the code is build, deploy and the device is restarted to immediately initiate the code you just deployed. Of course you can add a breakpoint and initiate a debug session by hitting F5.
Please do not forget to visit the nanoFramework landing page and ask for assistance if required or just to explore the eco system of nanoFramework or look for other boards that are supported.