You need to remove the four screws on the front. Open the casing and there are two jumpers right next to the wiring assembly for the display. Place the jumpers so that both contacts are covered. You will now be in "heating" mode. Replace the cover and you should see a little flame where there once was a snowflake. Now set your temp to the cut out (when you want it to stop heating) temp and you should be good to go. If you need more detail, just google the model and you should be able to find an operating manual without much difficulty.