How to Adjust Screen Brightness on Your Chromebook
You can use the screen brightness keys to adjust screen brightness on a Chromebook.
To change screen brightness:
Click the time or battery icon on the bottom-right corner to open the notification area.
You will now see the screen brightness slider.
Click and drag it to the left to lower the brightness
Click and drag it to the right to increase the brightness.
Read more here: https://www.chromestory.com/2016/08/c...