On A 3-way, there’s an extra terminal, called the “widespread.” Power comes in for the switch around the popular, then two “traveler” wires link the primary switch to the 2nd over the brass terminals. The switch is easy to include to an current Wiz system, but has relatively confined operation. https://franciscorvpfi.tblogz.com/the-definitive-guide-to-smart-switches-48260356