Locate the on/off switch for the stopwatch. In some cases, there's no button with this specific title, and the device activates when you press any button.
Verify the display on the stopwatch's face shows all zeros.
Press on the button labeled "Start" to begin the timer.
Stop the timer at the desired moment by pressing on the "Stop" button. In some cases, this button is the same as the "Start" button, with a "Start/Stop" label.
Prepare the stopwatch for additional timings by pressing on the "Reset" button.
Repeat Steps 3 and 4 for additional timings when the display on the stopwatch's face shows all zeros.