Switch on the thermometer by pressing the on/off button. When the display shows the currently selected mode, press and hold the on/off button for approximately 3 seconds until the display flashes. You can now switch between the modes by pressing the on/off button again. Once you have selected a mode, simply wait until the message stops flashing and the thermometer displays 3 dashes ( - - - ) and a measurement icon indicating the thermometer is ready to measure. You can now proceed to the temperature measurement.