In the series of talks I will explain some ideas behind categorifications arising from representation theory. We will start by looking first at basic examples of Heisenberg categorifications due to Khovanov. The goal hereby is to get a feeling for the involved 2-categories and the background of the graphical calculus. The goal is to give some indications how representation theorists would get natural candidates for the space of 2-morphisms. In the second talk I will make the connection with Delignes universal tensor categories and their representations and indicate who categorifications can be used to get information back to representation theory. In the third talk I might explain some more recent applications to knot theory.