For people with hard disk installation issues, please check your bios/uefi settings. There *might* be a setting there about Windows 7 compatibility and Windows 8/10 compatibility. Toggle it on and off as appropriate.
For people who cannot install on older or incompatible computers, as long as it can already run W10 64-bit, my advise is to take out your drive, plug it in another computer which can install this build, install Windows but once it counts down to restart (before Windows actually installs and configures itself for that computer) turn the computer off, plug it back into the computer you want to use it on, and turn it on. Make sure your bios/uefi settings are properly set.
There are better ways to do this but this requires the least explanation without complicated instructions. If you need more specific instructions, you might want to rethink why you are installing a developer build. It goes without saying, do not do this if you only have one drive and you don't want to lose your files. And don't blame me if your computer breaks, burns down your house, or teaches your dog to fart on your face.
I also have tips once you are able to install this; you might want to check my earlier posts.