Most smart switches need a neutral wire, which lets your smart light switch stay powered up and connected to Wi-Fi always. When your home was created before 1985 (plus the wiring hasn’t been up-to-date), you could absence that important wire. If that’s the situation, then I like to recommend using https://martinkutrs.ageeksblog.com/33630650/smart-power-points-and-switches-an-overview