Adjust the Brightness on Your Galaxy Book
Adjust the brightness to reduce eye strain and conserve battery life.
Using Function Keys
You can adjust the brightness using the keyboard. To lower the brightness, press and hold the Fn key and then press the F2 key. To raise the brightness, press and hold the Fn key and then press the F3 key.
Navigate to Start > Settings > System > Display.
Drag the bar under Adjust brightness level to increase or decrease the screen brightness.