Wimlib and some terminal/command prompt usage. The process is straightforward, but requires one third party tool called Windows 10 disk image (ISO) file from Microsoft.
If you haven't already done so, you'll need to download the
This is a quick 'how to' guide to make a bootable Windows 10 USB drive/stick Split size (previously 4000 MB) and suggesting legacy BIOS mode. Update : Thanks to Parul Jain for emailing in with the 3800 MB