1. Add music to the video editor with the upload button.
  2. Click on the uploaded file to enable controls.
  3. Click on the editor button .
  4. Set the value of the speed parameter in the opened editor, where:
    Original speed.
    Slower / Slow down music.
    Faster / speed up music.
  5. You can go back to the main editor and edit the video further or just click the "Make Video" button.