Press the up and down arrows simultaneously for 3 seconds and release. You will see F for Fahrenheit or C for Celcius. Press the light button or wait 3 seconds and the first stage differential will show. It is adjustable with the arrows fron .5-3 degrees in .5 degree increments. Press the light button or wait 3 seconds and you will see the second stage differential. It is adjustable with the arrows from 1-6 in .5 degree increments. Press the light button or wait 3 seconds and you will see the second stage delay. It is adjustable with the arrows from 5-40 minutes in 5 minute increments. You can either press the light button until you return to the main screen or leave the thermostat and it will return on it's own.