Make sure you are running the public release of Windows 10 (version 10.0.10240 or better).
You can find your current build number by clicking the start button, typing "winver", and hitting the Enter key.
If you're not running Windows 10 (version 10.0.10240 or better) you can upgrade from here.
Follow the instructions and when prompted allow the USB driver to install by clicking "install".
The mounted virtual drive contains an installer file "Windows_10_IoT_Core_for_QCDB410C.msi". Double click the file to start the installation.
The installer creates a new directory: C:\Program Files (x86)\Microsoft IoT\FFU\QCDB410C\ which contains the DragonBoard410c image file "flash.ffu".
Unlike Raspberry Pi 2 or 3 and Minnowboard Max, we will not be applying this FFU to an SD card. Instead, we will use this flash file on the next page.