To edit a timer, select the timer you would like to edit and simply swipe up on the bottom control bar.
From there you will be able to edit the name, duration, repeats, color, sounds, and more.
To edit a timer for list view, right-swipe on the timer and select the edit icon (pencil icon).
Your options to edit will be the same, but you will need to press “Save” in the top right corner to ensure your changes are saved.