1)From the Topic List pod, select one or more topics.
2)Click the Properties button.
3)Click the Appearance tab.
4)In the Background Sound box, enter the name of the sound file. The following formats are supported:
Used on UNIX systems. Supported by Microsoft Windows and HTML Help.
Musical Instrument Digital Interface. Standard for synthesized sound from electronic instruments.
The native sound format for Windows.
5)In the Sound Loop Count box, enter the number of times to play the sound file.