Mobo replacement

Ok, I've got to strip out my old mobo (Asus Maximus viii extreme Z170), for an RMA. I need to know a few things.
1. In the manual it says that I can save the bios and overclock settings to USB. Has anybody done this before and can you talk me through the steps please.
2. Is there anything I should be doing in case it all goes wrong (ie. reinstalling windows or similar).

just tried to save bios to usb but nothing seems to happen. Using a fat32 formatted usb stick in the bios update usb port on mobo. There is only one choice of what drive to save it to (in this case "F") but my drive is actually "G" ??