You will need: ISO of Windows and USB 8GB or higher
Start with opening “Terminal” and typing in the following command:
diskutil list

Then we want to format the drive to the correctly so use this command:
diskutil eraseDisk MS-DOS "WINDOWS10" MBR disk2
Now lets virtually mount the Windows ISO, you can do this by just a simple double click .
Now let copy the files over to the already formatted USB drive
Open Terminal and use this command for 32bit OS:
cp -rpv /Volumes/CCCOMA_X86FRE_EN-US_DV9/* /Volumes/WINDOWS10/
and this for 64bit OS
cp -rpv /Volumes/CCCOMA_X64FRE_EN-US_DV9/* /Volumes/WINDOWS10/