As mentioned in lesson 13, there are four cases in German. The cases refer to the very specific ways we must speak about anything in German. The four cases are the Nominative, the Accusative, the Dative, and the Genitive. In German, these cases are called Nominativ, Akkusativ, Dativ und Genitiv.
It's easiest and least frustrating when you learn them one at a time, and we're even going to leave one of them out because you don't need it as a beginner. The Genitive is the case we're going to leave out completely.
Review the transcript, study the lesson and do the quizzes: www.newsinslowgerman.com/series/guts/15/transcript