30 Day Fit Challenge Workout is a fitness app which helps in workout.
Simply, if you want to try the app without any trainer then I recommend not to follow the app. Because this app tells the exercise and the way of working it out, but without a trainer or instructor you may damage your body.
These kind of apps are only for knowledge that you are soing all exercises or not. You can usr this app to traack your workouts, i.e, to memorise that the particular exercise has been performed or not. Other than this, there is no use of this app.
So I recommend that if you are a starter exercise the workouts only in presence of an instructor otherwise you will harm yourself.