For dell
-plug win10 usb (uefi and secureboot ready)
-f2 setup
-enable uefi boot, disable legacy option rom boot, enable secureboot, enable ahci
-go and add boot option
-give it a fancy name
-choose usb under FILE SYSTEM LIST (look carefully to see USB written in one of several entries and choose it)
-click … dots
-find bootx64.efi under efi\boot directory (FILE NAME entry should look like \efi\boot\bootx64.efi
(If you have a small netbook you may need to choose bootia32.efi file)