Can anyone tell me how to transfer my music files to my sd card?

[AC Question]

I have a rather large library.

 

[Rukbat]

Plug the SD card into the computer (use an adapter). Open the card (in Windows Explorer, if you're using Windows). Open another window and navigate to the top of the music folder tree (Music, or wherever you keep it). Drag that folder to the SD card. Go for lunch, it'll take a while.

(Don't use a USB hub, connect the card directly to the computer. Most USB hubs fail from overheating if pushed to move a lot of data. [They recover, but you don't get all the data transferred.])