Tested with Windows Server 2016.
This lists the quick steps to create a bootable Windows installer on USB disk without using extra tools.
Follow Thomas Maurer - Create a USB Stick for Windows Server 2016 Installation.
In short:
diskpart list disk select disk 1 clean create partition primary format fs=FAT32 quick active assign letter=k exit
robocopy d:\ k:\ /E /XF install.wim /XF autorun.inf
dism /Split-Image /ImageFile:D:\sources\install.wim /SWMFile:k:\sources\install.swm /FileSize:4096