More specific guidance in videos and instructions
The videos and written instructions are okay, but not specific enough in their language. For example, sometimes the written instructions say, "Keep body vertical to floor," but the move involves bending over. It's important to be more specific, such as 'Keep torso vertical to the floor." It would also be really helpful if each move told you which muscles you are targeting, and where you should feel the move or pressure or effort in your body (specifics like, in your thigh, in your calf, in your abs).