turn RGB lights on
Device menu, this is where you can find both joycons.
here you can highlight both joy-cons or left only/right only to have different lights on both.
Clicking 'Music' allows you to play music that the RGB lights react to.
'Tape' is Similar to music how ever uses the phone mic to pick up sound from game play and will also react to this
Choosing style much like 'Mode' in V3 you can preset 'breathing' , 'strobe'
and have fun with changing RGB lights.
clicking the setting icon you can change the wallpaper and even choose shake, so your joycons will change a different colour light each time your phone is shaken