You need to download the ARM64 Windows 10 Insider Preview, however, you won't be able to access it if you are not part of the Windows 10 insider preview. Download Insider Preview Windows 10 for ARM (Windows10.VHDX) If you want to get the Windows 10 running easily in a few steps on your Mac with an M1 chip, follow these steps. If you are one of those lucky persons that own one of the brand new Macbooks with an M1 chip and work with virtual machines, you may have encountered yourself that the traditional way with VM-Ware doesn't work or you need to configure a lot of stuff that you may probably not want to understand. Now, thanks for the Fall Creators Update, Windows 10 will be able to run on the ARM CPU architecture, providing you with great application compatibility, allowing you to run existing x86 windows applications without modification of the source code.
Windows as we knew it a couple of years ago, could only run on PCs with processors of 86 and 64 bits.