Pin switches will enable a user to send a high or low signal through the GPIO pins. This can turn on devices, LEDs, or trigger other devices like relays. No special wiring is needed, however make sure each pin complete a circuit.
NOTE, pins on the left side provide +3v and on the right provide +5v. If your device requires one or the other, be sure to select the appropriate pin side.
Further, you may elect to have a pin go low on command, this can be useful for either turning off devices, or triggering devices.
At the core, a high signal is delivering +3 or +5v to the pin, where a low delivers no voltage.