For a video-based course where the audio is a supplement, it is commonly recommended to put your audio files in the download section. When the audio file is put in the download section, that means that your customers can download that file and have it stored on their devices.
This concerns many people who are just having audio as the main media of their course. If this is your concern, in this course we will cover how to prevent audio files from being downloaded.
Another common concern is how to support the visual learners who will be in your audio-based course.
If this was your question or concern, here is how I would go about supporting all types of learners. What you can do is you can create visual graphics or handouts that correspond with each specific audio lesson.
If your audio lesson is teaching new ice cream truck owners how to pick the best ice cream for their new ice cream truck, then you can provide an image breakdown of what types of ice cream they should add.