Works just like a regular physical kitchen timer. There are no buttons.
Start the timer
Swipe up to set the time you want and release.
Change time
Swipe timer to the new time and release.
Stop timer
Swipe timer fully down.
Timer limit
In settings, you can change a maximal value of timer. Choose between 5, 10, 15, 20, 30 and 60 minutes.
Light vs Dark
This app has 2 color themes. Light and Dark. Choose the one you prefer, or leave it to automatic.