audio over several slides

I am using Captivate 8.

I have an mp3 file that I need to play over several slides. So basically, I want the file to keep playing, while the slides move on without the user having to click a button.

I imported the mp3 file, and set the timings of the slides themselves to progress automatically. However, when I play my project, the audio file starts playing on slide 1 and then continues playing for the full 50 seconds (i.e. the slide doesn't move on). This is despite the fact that I set the timing of the slide to move on after 10 seconds. When I look at the timing properties again, the time has changed from the 10 seconds I had set, to 50 seconds as the length of the mp3 file.

Can anyone help please?