Before you really start using the sensor you want to insulate the board from your (naturally) sweaty/oily
fingers. The Pulse Sensor is an exposed circuit board, and if you touch the solder points, you could short the
board, or introduce unwanted signal noise. We will use a thin film of vinyl to seal the sensor side. Find the
small page of four clear round stickers in your kit, and peel one off. Then center it on the Pulse Sensor. It
should fit perfectly.