On a three-way, there’s an extra terminal, called the “prevalent.” Power comes in to your switch around the popular, then two “traveler” wires hook up the very first switch to the 2nd around the brass terminals. The switch is easy so as to add to an current Wiz system, but https://p-hubsystem31850.blogocial.com/5-easy-facts-about-wiring-to-lights-described-70539313