MIDI through usb

Right now I'm just using the USB on the arduino itself, If it can't then I'm going to get a MIDI port then a MIDI to USB converter. I've also just used random free ware stuff I've found online, if you can let me know where the code you had was that would be very helpful. I think my biggest problem with the stuff I've found so far is it is just there are no instructions on how to use it.