Once you know the engine displacement, you can find the firing order in a Ford repair manual specific to your Ranger's year and engine. You can also often find this information online by searching "[your engine displacement] Ford Ranger 1993 firing order".
The firing order is not simply a numerical sequence (1,2,3,4...). It's the order in which the cylinders fire their spark plugs. This is crucial information for things like diagnosing misfires or properly connecting spark plug wires.