If you want to listen to the recording, click the play icon next to the sound track name. Use the search box to search for tracks or click the Recommended tab.
When you find the track you want, click Save - it will be added to your video. You can determine the location of the tracks by matching the audio panel below the video.
After you click Add to Video and select an audio track, its name will appear in the highlighted bar below the player. Click on that bar.
You can now determine the length of the audio track and its place in the movie. Just click the beginning or the end of the line and drag it to the left or right. After trimming the audio track, drag it to the desired location in the movie.
This function allows you to define the place where the audio track snippet should be played in the movie. You can adjust the sound volume so that you hear only the music, or more of the original sound, or both soundtracks.
If you need to extract audio from video try Youtube to Mp3 Converter.