In addition to the stopwatch, the clock app on the OnePlus smartphone also has a timer function that runs a fixed time or countdown and alerts us with a timer sound.

After the desired time has been set, the timer can be started and paused at any time.

Note: In this guide we set a time, start the timer, pause it and reset it.
The steps mentioned above are for illustration purposes only and can be skipped in part.

Android 10 | OxygenOS 10.0
Step 1:  Open the  Clock app
Step 2:  Tap on  Timer
Step 3:  Choose  Hour / Minute / Second
Step 4:  Set the  timer
Step 5:  Tap on  Start
Step 6:  Tap on  Pause
Step 7:  Tap on  Reset/Delete
  1. Open the Clock app
  2. Tap on Timer
  3. Choose Hour / Minute / Second
  4. Set the timer
  5. Tap on Start
  6. Tap on Pause
  7. Tap on Reset/Delete