How do I light up different LEDs?

Fork the FireStep repository and change NeoPixel.cpp, which maps display status to LED pyrotechnics: https://github.com/firepick1/FireStep/blob/master/FireStep/NeoPixel.cpp FireStep uses display status for semantic lighting control–it really doesn’t care what LEDs do what and you could even hook up the display status to a subwoofer to rattle you on error if you like.