Activate lighting
To cycle between the five preset brightness levels, press the FN and F7 keys at the same time. For more information, please see Game Mode and backlight control on the G413 gaming keyboard.
NOTE: The G413 Carbon features red backlighting and the G413 Silver features white backlighting. 

Customize lighting settings in Logitech Gaming Software
You can use Logitech Gaming Software (LGS) 8.92 and later to customize lighting settings for your keyboard. Use LGS to adjust the fixed brightness level or enable a breathing effect. If you don’t have Logitech Gaming Software, you can get the latest version from the LGS Download page.

Launch LGS, select your G413 gaming keyboard and click the Lighting Settings icon.

The Lighting Settings window appears:

• Use the Brightness slider to adjust the fixed brightness level. Drag the slider left to decrease the intensity of the lights and right to increase the intensity. 
  NOTE: Drag the slider all the way to the left to turn off/disable the keyboard’s backlighting. The FN + F7 shortcut can not enable the keyboard’s backlighting if it has been disabled in LGS.
• Click the checkbox to enable an effect that simulates breathing. You can adjust the rate of the effect using the slider. Drag the slider left to slow down the effect and drag the slider right to speed up the effect.