Others have detailed the basic use but I'll add my comments. With the engine off, familiarize yourself with the stationary numbered scale and the notch in the lower pulley so you'll know what to be looking for. You may have to reposition the engine pulley with a short burst of the starter to find the notch on the rear lip of the pulley. You might need to feel with your finger for it. Either wipe it clean or put a small dot of paint or nail polish on the notch to make it easier to see.

With engine still off, connect the wires to battery and spark plug wire, hold the timing light above the height of the engine and point the light toward the lower pulley. Move the light around as though you are using a flashlight looking for the right angle to point it. The light won't blink so you'll have to pretend. If any of the wires can drape near ANY pulleys, belts or the fan blade - reroute them under hoses or tie them away. VERY VERY IMPORTANT!... the strobe light will make moving things look like they are stationary. Get your fingers or tools too close and you will find out that they are moving. Do not lower the light any closer than the top of the radiator. If the distributor needs to be loosened to change the timing, do it with the engine off and leave the nut "drag tight" so you can turn it easily and it will stay there. Tighten nut with engine off and start engine to recheck. Do not put your tools above the radiator where the wire or your free hand could knock them into the fan.

Get everything in place and double checked before you start the engine. If you have a helper, allow nobody to stand in line with the fanblade while the engine is running, even for an instant... just in case you drop something.

Learning is fun but you have to finish the job with the same number of fingers and eyes that you started with.

As a first timer, you need to keep the safety part as a priority ahead of whether you succeed in properly setting the timing or not. KEEP THIS IN MIND - any time the engine is running, the front of the engine is off limits for hands, wires and tools - even though it looks safe.

'nuff said.