Click on a slide to advance it or use the VCR controls.
Select Slide Show Sound tab, click on the sound box, click on the green X and then browse and select for your music files. You can control the quality, looping, synchronization and fade out.
To add narration or effects to a slide, double click on the slide, select the Slide Sound tab and browse and add sound clips. You have several timing choices. select Set Slide time to sound time will automatically match the slide duration to the sound byte.