Timing is pretty basic, most all the newer lights have an inductive clamp(older ones plugged inline between the plug & wire) that clamps over the number 1 plug wire, and also has two power clamps for the battery, or in this case I clamp to the starter solenoid, and my AC bracket as my battery has covers on the terminals. You then shine the light down toward this are, and everytime number 1 plug fires the timing light fires it's strobe light so that you can see where the mark on the balancer is with regards to the marks on that scale. You then slightly loosen the distributor clamp bolt and twist the distributor to move the timing advance or retard as required.
One final thought, that inductive clamp has an arrow or a towards engine side, this is important as not all of them work well backwards. My favorite old Craftsman light is 30ish years old, and works better than the two newer ones that I have, BUT I HAVE to put the clamp on the right direction, the newer ones aren't picky, but they also aren't as accurate.