How do you put music on a Nintendo 3DS?

Take the SD card that comes in the 3DS's SD card slot and put it in a computer. Then click DCIM, then click on 100NIN03.once you have done that you can make a file named music enter that, then copy and paste the songs onto the SD card and put it back in the 3DS, then open Nintendo 3DS Sound. And hopefully the music should be there and you can listen to it. :)