1. Install companion app from Google Play https://play.google.com/store/apps/details?id=com.carsifi.adapter
1. Connect the adapter to the Android Auto USB port in your car
P.S.: you only have to go through this process once. Carsifi will connect to your device automatically afterward just make sure Bluetooth is enabled on your device.
P.S.2: If your phone no reacted on Carsifi adapter and the Android Auto session not established(you haven't seen any changes on your phone), please check if Wireless Android Auto is enabled on your phone(usually enabled):