Click the music note icon (♪) to open the background music list. Next, click the plus (+) icon to select the desired music files. You can change the order of the list by using your mouse to drag and drop the files.
The order and length of the songs will be displayed as a wave along the bottom track of the timeline. Here, the songs can be rearranged, shortened, and overlapped, and you can adjust the volume by using the volume rubberband.
Note: Sounds are not background music. You can drag them from the toolbox directly to the timeline or assign them directly to an image. The are no limitations on the number of sounds that can be simultaniously played.
If you would like to learn more about background music in SlideShow 9, look under "Background music" in the online help.