An exposé illustrates the scheme for bachelor and master theses. The following literature might be useful for the creation of your exposé and the selection of relevant content.

Kersken, M (2009) Anleitung zur Erstellung eines Exposees - Zur systematischen Planung einer Haus- oder Abschlussarbeit. (https://www.uni-due.de/imperia/md/content/politik/anleitung_exposee.pdf

Obviously, an exposé cannot be devoted to all the questionings of a bachelor or master thesis, but it should always have a focus on it. 

If you need a template for the creation of your exposé, you are welcome to use this MS Word template.