1. Pick up a microSD card and USB card reader. (Or if your computer has a card reader)
2. Insert the microSD card into the phone's microSD slot. Note: Be careful where and how you do this. The card insertion requires the use of fingernails, the spring mechanism to eject the card.
3. On the phone choose Menu, 9. Settings & Tools, 9. Memory, 3. Card Memory, Options, Format. This will format the card, and it will also place some folders on it for My Music, My Sounds, My Videos, etc.
4. Remove the microSD card from the phone, put it into the USB card reader, and insert it into the computer's USB slot. This should come up like any other USB drive.
5. Copy and past or Drag & Drop the desired Mp3 files to the cards