This app uses Pomodoro Technique, which is a time management method that break down work into tasks traditionally 25 minutes in length, separated by short breaks.
This is how you do with this app:

1. Remove all distractions.
2. Choose a focus task.
3. Start the timer that lasts 25 minutes.
4. Work on the task until the timer rings.
5. Take a 5 minute break.
6. Every 4 sessions take a longer break, perhaps 15 or 20 minutes.

Hope it helps you to focus on your productivity and beat procrastination.
Thanks Yi for helping with the design.