This app is one of beginner projects of development in android in order to learn java. It's a pretty simple app with a fairly simple ui for all age groups, with a start screen and then the rest of the screen has multiple exercises to choose from which when you choose will lead you to steps and a hyperlink redirecting you to a youtube video for the specific exercise.
I have also included the apk in the download incase anyone wants to check out the app first hand!