Choose a health behavior of your own and then apply one of the 3 theories from ASP text. Each person try to do either a new health behavior or different theory. For instance, I might choose drinking 8 glasses of water a day, and would then go through the 5 stages of change. Be original with your example.
Reading 1: https://www.clinicalcorrelations.org/2015/09/18/theres-an-app-for-that-fitness-apps-and-behavior-change-theory/