How to generate sound output to change led colors

Hi, i am trying to make a playlist of say 3 songs, piano notes, or some beats in max/msp and then send the output to change rgb led colors. what i have so far is a button that controls the rgb led turning it on/off in arduino only. I know I can use the serial port from max to send the output to arduino but I have no idea how to do that or even how to make a playlist of songs or beats. please help me thanks