Music can be an excellent way to establish the mood of your movie, and adding music is easy in Windows Movie Maker. First, find the music that you want to add to your movie and import it into your project. Second, add the music to the timeline on the Audio/Music track and edit it to create just the effect that you want.
Click File, and then click Import Media Items.
Browse to the file that you want to add, and then click the file. You can import audio files with the following file name extensions into Windows Movie Maker: .aif, .aifc, .aiff .asf, .au, .mp2, .mp3, .mpa, .snd, .wav, and .wma.
Drag the music file to the Audio/Music track of the timeline.
Use the preview monitor to preview the accompanying video, and then drag the audio track to the right or left to better synchronize the audio and video, if needed. The pointer turns into a hand when you click the audio file, indicating that you can move it.
A quick way to adjust the volume of an audio clip on the Audio/Music track is to right-click the clip, and then click Volume. Adjust the volume with the slider.
You can add both music and narration to the Audio/Music track in Windows Movie Maker. Both can play at the same time in your published movie. You can then adjust the audio levels to determine which audio will play louder than the other in your movie.