The buttons on the upper left side of the keyboard controls the lighting effects of this keyboard. The first will control the brightness. There are four brightness levels. The second button will switch between each lighting effect (Solid, Breathing, Trigger, Explosion, Wave, and Custom). The third button is for Game Mode and is also used for the setting.  

The custom setting allows you to select specific keys to be lit. To select the keys to be lit in custom mode, first switch to custom mode (the WASD, 1234, left CTRL and space bar keys are lit by default). The hold the brightness and game mode key down together until the backlight turns completely off. Press the keys you want to lit. When finished, press the brightness and game mode keys together again to save these settings.  

To reset the custom keys and brightness settings back to default, press and hold the brightness, lighting effects, and game mode keys at the same time until the backlight blinks twice.