The app automatically starts with the first day of the first level.
In order to start your training, simply tap "Start Training" at the bottom of the screen.
Right above the exercise preview, you will find information about the next training session.
It will show the date of your next session.
In order to change the date or level, simply tap the date. Here you can change both the date and the level.*
You can also tap the menu icon in the upper right corner followed by "Choose a training date".
* All three levels are available for you in the Full Version of the app.