1. Click the Audio Effects button-->click the desired audio effect icon.

2. Click the Music button-->click the Add Music button, then select the background music you’d like to add or upload. 

Once you select background music, it will appear under the Music tab. To play it, click on the music title. You can set the play mode to repeat, repeat list, or no repeat. Additionally, you can adjust the volume by clicking the Low, Mid, or High buttons.