Basically, saying a command will show a centerprint on your screen saying the music, while playing it in vehicle stereo. Saying it again will choose the next song.
Ex.
/ns ---> Plays the first/next song on the list in vehicle stereo.
(next song)
/ls ---> Plays the last/previous song on the list in vehicle stereo.
(last sone)
Say this is my music list:
Get Ready
Hyperdance
I'm Blue
I type "/ns". It will play "Get Ready" (Vehicle Stereo)
I type "/ns" again. It will play "Hyperdance" (Vehicle Stereo)
I type "/ls". It will play "Get Ready" (Vehicle Stereo)
I type "/ls". It will play "I'm Blue" since it's the last song from the first. (Vehicle Stereo)