The phone must first be connected to your wireless network before initiating the Wi-Fi set-up on the switch. Then you run the app's auto-search. It works almost like WPS (Wi-Fi Protected Setup) that you find on routers. In fact, if you could actually use WPS on your router and forego the app for set-up, it might be easier to get up and running.
Control smart lights with just your voice
Control the Mirror Smart Light Switch using your voice with Google Home, Alexa, and Siri.**