Native boot is a method that enables the computer to boot from the virtual hard disk (VHD) without the need for virtualization. It works in a way that adds VHD to a boot loader and boots from it. On the VHD disk, the Windows 10 deployment image is applied. Then, you have to configure your computer to boot from the VHD disk. Once you restart your computer, you will be prompted to boot from the VHD disk instead.
You can learn about deploying Windows with a VHDX (native boot) at https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/deploy-windows-on-a-vhd--native-boot.