Hi,
Take a look at this example: of using a pot to set a point (for lighting in this example):
And HERE: is info on measuring temperature.. Those DS18B20 sensors are good for getting a actual temperature value. You could also show outside temperature, coolant temperature etc,
And.. HERE: is an example of displaying multiple temperatures on a small LCD display...
When you get individual parts working, HERE: are some hints on combining multiple sketches.
Let us know how it works out...