Where do I connect the two lead wires?

When the button is depressed, this switch breaks the hot, or positive line, while the neutral and ground if needed, go straight to the electrical device, such as a light or motor. When the button is released, a spring returns it to off. It will work off and on just as well if you take the hot or positive to the neutral side of the electrical device and break (with the switch) the neutral line, but then the motor or light will ALWAYS BE "HOT", a very bad idea. Make sure that the positive line goes through the switch and never further unless you switch it on by pressing the button. The "Normally Off"as stated in the description is incorrect. NO means Normally Open, which is off but that leaves Normally On as the opposite, both NO. Proper usage is Normally Open and Normally Closed where the circuit is closed for continuity, passing electricity.