You can do several courses at the same time in the 7Mind app. The progress of each course is saved, even if you switch back and forth between the courses. You can only restart a course after you have completed all 7 meditations of the course.
In the library (at the bottom left of the screen) you can choose a course. Now, you can either start the course as a whole by tapping on "Begin Course". The next time you open the app, the coach will suggest the following unit and you will see future meditations of the course in "My Journey" (main menu at the top right of the screen).
Or, you can also start single meditations from the course by clicking directly on the desired unit in the library. Your previous meditations are displayed in "My Journey" so that you can follow where you are at any time.