Navigating GIGABYTE's X570 UEFI
You enter the BIOS/UEFI by hitting the "delete" button when you see the post code "b2"(or "62") or when your keyboard's "number lock" light turn on. Once in the BIOS, hit "F2" to switch from Easy Mode to Advanced Mode. Once in the advanced mode, go to the "Tweaker" menu by hitting the right arrow key once. It's easier to navigate the UEFI through the keyboard, and to enter in a multiplier you can type it in, same as voltages.
The mode above is the Easy Mode of the UEFI, you will be able to see many things, but you cannot overclock in this menu. If you need to control fans you can hit "F6". If you need to load optimized default settings, you press "F7". To update the UEFI you press "F8" to get into Q-Flash.
To save and exit press "F10" and you will be greeted by a list of all the changes you made that will be applied. You can also just type in settings, so if you want a x43 multiplier you just type in 43.