Music design takes as many forms as music itself. So before teaching it, determine which form to teach first. Consider the following-

Music designs can be:

For digital and/or live performance
Performed live and/or in a studio
Performed by acoustic and/or digital instruments
Recorded or not
Notated or not
Designed by one or more designers
Performed by the designer and/or other musicians
Tailored to specific performers or not
Anywhere on a spectrum from controlled to improvised
Designed from scratch or utilize existing material
Experienced alone or paired with additional elements such as image

Each possibility contains trade-offs. What makes the most sense for you and your students?