You can download gigabyte motherboard utility and do the update automatically through the utility program. (Although it would seem that doing it this way has a greater chance of failure to update and ruins the motherboard. But this was a big worry many years ago, since there have been big improvements in the utility updates), I've done this with my Asus utility many times... Always easy and fast...
Or, ultra safe way, download bios update (for your motherboard, will be in drivers section). Put it on a usb. Restart computer, enter bios (F1, or delete button will get you in on initial startup screen), you'll find a bios update option in there, just have to select your drive/path (can't give exact directions to where to find bios update...