That's a very good explanation of IGNITION timing, DOC. There's also VALVE timing, a different thing, that may be confusing kais3. The timing belt that connects the crankshaft to the camshaft must be set correctly, it's not an adjustment per se as it's either spot on or it's wrong.
Doctor Bill's second picture shows the valve timing, when #3 is on 0, the timing belt determines whether #'s 1 and 2 align. This must be right first or setting ignition timing is a waste of time.