How to enable battery saver on my Nothing phone (1)?

- When the phone (1)'s battery falls below 15%, a low battery notification will appear to prompt you to turn on battery saver.
- To toggle it manually, swipe down from the top of the screen two times to access the expanded Quick Settings. Press the edit (pencil) icon and drag the Battery Saver tile up from the hidden tiles. Tap it to toggle it on and off from the Quick Setting.