Attach a USB media card reader to your computer if it does not have a media card slot. Some desktop and laptop computers have built-in media card slots that can read an SD card.
Download music files to your computer if you do not already have the files on the computer.
Insert the SD card into the media card slot or USB media card reader. It will appear on your computer as an additional removable drive.
Use “My Computer” on a PC or “Finder” on a Mac to open the SD card in its own window. Use another window to open the folder where your music files are stored.
Select the music files that you want to put on the SD card. Drag and drop the files into the SD card window.
Wait as the music files copy. When the transfer finishes, you can remove the SD card from the computer. It will have the new music files on it.