here's a '75 so basically your 74 should have the same layout.
Lower left terminal on an angle with the yellow wire going to it should get power only when the key is in Start.
Here is the scheme for the headlight switch.
Some colors may be different on your car since this is based on my '67 Barracuda.
The yellow wire from the dome light is not the same as the yellow wire to the starter relay. In the factory diagram (shop manual) each wire has a label to make that clear.