How to make "floppy disk" RAID Driver in Asrock Extreme4Gen3?

You need to go thru the User manual for that.
They would give you a CD/DVD with the Mobo that contains a Zipped file which you would need to uncompressed onto a Floppy Drive or a USB stick, and when asked for the drivers you'll need to guide the OS installation process to the address where you uncompressed it.