2. click the icon in the upper left corner and select "add files to the library", or drag the music directly to the blank space in the music library.
3. after adding, click "iphone" in the upper right corner to enter "Administrator's iphone" settings.
4. click "music" on the menu bar to enter the music setting interface. if "synchronize music" is checked, click "synchronize" in the lower right corner.
if it is not checked, check "sync music" and click "apply" in the lower right corner.
5. Click "On this iphone" on the menu bar, and you can see the songs that have been added on the iphone under the "Music" option.
6. Click "Done" on the menu bar, and then click the pop-up icon next to "iphone" in the upper right corner to unplug the iphone data cable.