Add Music to a PowerPoint Presentation

 To add music to a PowerPoint presentation that plays throughout the entire slideshow and set slide timings, you can do the following:

1. Insert music: Select the Insert tab, then Audio, and then Audio on My PC. Select the music file you want to use, then click Insert. 
2. Set music to play in background: With the audio object selected, open the Playback tab and select Play in Background. This will automatically start the audio file and play it across multiple slides. 
3. Add slide timings: Click the Transitions tab, then under Advance Slide, check the After box. Enter the number of seconds you want each slide to display. 
4. Apply timings to all slides: Click Apply To All. 
5. Check Use Timings: Click the Slide Show tab and make sure Use Timings is checked. 

You can also record your own audio to add to your presentation.