The words you want to remember while setting the timing is
top dead center ready to fire.You want both valves closed.They make a tool that inserts
in the spark plug
hole that whistles as you rotate the crank to alert you that both valves are closed.Or put your
thumb on it and feel the pressure.You want to be TDC on the compression stroke which is 180 degrees opposite of TDC of the exhaust stroke.Both TDC will read 0 on the crank timing ring.