As with anything that you want to teach others, you should become very good at it yourself first. Teaching exercise to music requires being able to do the exercise to music first. Then you find what type of cueing works best for you and clients. Break the exercise into it’s base parts and learn how to verbally instruct as well as visually instruct the parts as necessary. And a lot can be learned as you teach. What was effective? What was a flop?
I hope you have done well and this has been a success for you.