How do you add an audio clip from your computer to a video that you are editing in motionsd studio?

How do you add an audio clip from your computer to a video that you are editing in motionsd studio? its the video editing software that comes with Panasonic cameras.

If you want to add audio files to video, I find a perfect program and step by step user guide at http://www.videoeditorsoft.com/how-to-add-audio-to-a-video-file.htm.

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