I was shocked when I have realised I must have Windows 10 running on my PC to get the W10 preview for my Raspberry 2.
Since the installation process is about to simply put a image file on a SD card, I was pretty much certain that no need to install the Windows 10 for my PC first.
After acquiring the .zip file (the Google and torrent sites will help if the Microsoft site fails to deliver the free software) just download the proper imaging tool (also free) from the Microsoft site: https://go.microsoft.com/fwlink/p/?LinkId=526740 (download the Technical Preview, run the installer, untick all the crap you don’t need just keep the Deployment Tools), then follow the official documentation: https://ms-iot.github.io/content/win10/SetupRPI.htm Errr… more or less, the correct command should be like this:
C:\Users\fisher\Downloads>”C:\Program Files (x86)\Windows Kits\10\Assessment and Deployment Kit\Deployment Tools\x86\DISM\dism.exe” /Apply-Image /ImageFile:flash.ffu /ApplyDrive:\\.\PhysicalDriveX /SkipPlatformCheck
Then enjoy the IoT Preview.
Actually I think it was waste the time to download and flash it because it is accessible via powershell only and no apps or anything installed in it.