I don't use one, I use a heat lamp but should show you in the instructions. What you wanna do it place it so it's half the wall, but above substrate, in line with the top so the animal can come in contact with it. You want to put a digital thermometer probe directly on the mat. You'll need either a on/off or pulse proportial thermostat to regulate the temperatures, the probe should also be in contact with the mat, on the inside of the tank