2. Open Windows Explorer or Finder on your computer.
3. Drag and drop the music files you want to transfer from your computer to the "Music" folder on your Xperia X10.
4. Disconnect your Xperia X10 from your computer.
5. Open the "Music" app on your Xperia X10.
6. Tap the "All Music" tab.
7. Select the music file you want to listen to.
8. Enjoy your music!
Note: If you are using a Mac, you may need to install the Android File Transfer utility in order to transfer files between your computer and your Xperia X10.