A narrow band gauge is really just a light show. For actual correct readings, you want a wide band gauge. But they are a ton more than the narrow band. Nothing wrong with it, but not really worth the hassle imo.
But generally speaking your gonna need to hook a wire to a ground, to a power source, the light bulb to your interior light switch, and finally splice a wire into one of your 02 sensor wires.
2000 Mustang GT-Former giggle gas addict
1990 Mustang GT w/ Vortech V3
***resident gun idiot***