Installation: Place the temperature sensor in the right place in the terrarium or the aquarium. There are different temperature zones in the terrarium. So you need to determine what temperature you want to control with the thermostat. Locate a neutral temperature zone (not under a heat lamp), slightly above the ground, is recommended. A current zone is recommended for an aquarium. Place the unit so you can read and understand it easily. Connect the corresponding jacks to devices you desire, the heat sources A, the controlled devices B. Connect the timer to the mains adapter into the socket provided. Make sure the devices are not connected once all settings are stored. Instructions available underneath.