i have a yamaha psr-225gm keyboard and i just bought a yamaha usb midi ux 16 and i am trying to use it with my new mac. I set everything up and when i plug it in I go to system preferences and get to Yamaha USB-MIDI Patch (32-bit). there's these 3 columns with 1s and arrows. what do i do now/how i actually transmit the messages!??