What to do?

Downloaded the App today and deleted it today. I was using it and was enjoying it, but when I needed to get out of it, it continued to play over and over the first 10 words. There is no way to shut it down when finished doing the lessons. What am I doing wrong? There is no main menu to go to and select to quit. What do you do? And really no instruction on what to do for the entire program.

Nilj about German by Nemo, v5.3.4