Use the brightness keys on your keyboard, usually the sun icons on the function row
Press the Fn key together with the brightness key if needed
Open Settings on Windows, then go to System and Display, and adjust the brightness slider
Open Action Center or Quick Settings and move the brightness slider
On Mac, open System Settings, then go to Displays, and adjust the brightness slider
Use the monitor controls if you are using an external display
Update your display driver if the brightness control is not working
Check power saver or battery settings, which may limit brightness
Disable adaptive brightness if it is reducing the screen brightness automatically