Hook up your timing light to your battery then the other box shaped clamp to your number one plug wire which is the one closest to the radiator on the passengers side, Then you pull out the snout connecter which is at the distributor and slightly loosen the distributor. You can make a mark on the harmonic balancer where you want to set your timing at this time. Then crank your car and aim the timing light towards the timing mark on the balancer and set it at the degree you want by rotating the distributor, I beleive if you rotate it towards the left it will advance it and to the right it will retard the timing. The tighten your distributor down and reinsert the snout plug.