With FNATIC OP software fully closed (exit from system tray) and the keyboard plugged in:

Press B+I+O+S+M and hold for 5 seconds.

Upon release, your keyboard lighting will turn off and on again to show it has entered BIOS MODE.

When pressing B+I+O+S+M hold for 5 seconds again (or unplugging your keyboard), upon release, the FNATIC sequence will show return to normal usage.