iOS
Touch and hold an empty area of your home screen, tap the + in the top corner, search for Durance, and choose a size. Durance supports the small widget size, plus circular and rectangular widgets for the Lock Screen and StandBy.
Android
Touch and hold an empty area of your home screen, tap Widgets, find Durance, and drag its widget onto your home screen. You will be asked to choose a counter as soon as you place it.
Either way, add a counter in the app first — a widget has nothing to show until at least one exists.