A blood pressure monitor is a must-have at home for keeping your numbers under control. It is a device that basically measures the blood pressure of a person by inflating and deflating the cuff to measure blood pressure. Here is how to use a blood pressure monitor: Place the cuff around your arm or wrist, turn on the device, and the cuff will inflate to start the measurement and deflate when the measurement has been taken. Once finished, the final reading will appear on the screen. The average reading should be around 120 for systolic and 80 for diastolic.