To open the "Stopwatch Timer" app, locate it on your device's home screen or app drawer and tap on its icon.

You can select either the stopwatch feature for measuring elapsed time or the timer feature for setting a countdown duration.

To start the stopwatch, simply press the "Start" button displayed on the app interface.

Yes, you can pause the stopwatch anytime by tapping the "Pause" button, allowing you to halt the timing temporarily.

To reset the stopwatch, click the "Reset" option, which will clear the current time and return it to zero.

For the timer, first set your desired countdown duration by inputting the hours, minutes, and seconds you want.

Press the "Start" button to begin the countdown timer running after setting your desired duration.

When the timer reaches zero, you will receive an alert or notification indicating that the countdown has completed.