Help changing bios settings

I was told to undervolt my cpu to helps with temps and one of the things I was told to do was set my ac/dc load line to 55 but the cup internal ac/dc load line option in bios doesn’t have number values the options are auto, extreme, turbo, performance and power saving. I’m using a gigabyte b760 ds3h ddr4 board. None of the settings allow me to do what I was told to do to undervolt my pc and I can’t find any helpful video on it.