There are several steps you need to do to use a food thermometer correctly. First, you need to make sure it is accurate to within two degrees, to do this you need to calibrate it. There are two ways to calibrate a food thermometer. The first is to calibrate using the ice water method. this is done by taking a drinking glass, filling it with ice, then adding water to the ice, then you want to insert the temperature probe into the ice water and once it gets to 32⁰ you then press the set button on an instant-read thermometer or turn the dial on a manual thermometer to 32⁰ and ut we calibrated. The second method is the boiling water method, it is not the safest way to calibrate a thermometer but it will work. First, put water in a pan, place the pan on the burner and bring the water to a boil, then place the sensor probe into the boiling water and press the set/to calibrate button and it will set to the water temperature which should be 212⁰. if you are using a manual thermometer you would then turn the dial to 212⁰.