This app is one of the simplest apps in the store. But you will use it a lot. Set an alarm when you are going to take a small nap is not too much work, but a timer is better! Just in two taps you will have a countdown running. There are ready-to-use naps with the common durations, or you can create new ones. You can also delete that ones not needed.
Take your time to explore the settings. You can customize the app to fit exactly to your personality. For example you can choose the snooze time.