so, you need to:

* Set up an ADC
* Tell it to read from the temperature channel
* Convert that reading (in ADC counts/voltage) to temperature
* Maybe calibrate that reading if you want it to be accurate

Though note, that temperature sensor is like "CPU Temp", not "Ambient Temp", so it will probably always read a little warmer than air temp in your room, and might change randomly based on how hot the CPU gets/how much code you are executing