Been awhile since I used Audacity. I actually use Kristal for all of my audio editing. http://kristal-audio-engine.en.softonic.com/
I am sure there is a way to set a track marker in Audacity or it might be a start and stop point. I also think there is a way to export your selection. Again I always use kristal because it is so easy to do just that by taking your track cutting where you want the start and stop and then clicking on that piece and hitting p. That will set the markers for just that piece.
I know it's possible in Audacity maybe try to find a youtube video on it.

I am back. I now have 17 slides and music playing throughout the slide presentation.

Here is where I get fouled up. I am trying everything suggested.

How can I now add narration. I am trying to add narration in Audacity as instructed, but it is not working.

Is there a way in PowerPoint 2013 to add narration to the slide presentation that already has music in all the slides. When I have tried this (Several times) the music got louder and drowned out the narration.

Also if I can do this, then how do I remove the music and narration icons from the presentation before I save.

Thanks for all the help.

Don