1983 2.8 turbo timing

Hood sticker on my 1983 280zx turbo has 24 degrees btdc. My Hayes manual does not adress how the car should be set up to check the timing and how to adjust it if it is off. Is there thing that needs to be unhooked before using the timing light? Is there a better manual that I can get for this car? Hood sticker engine # is DNS2.8V5FBF7