The integration of technology into STEM education has been shown to increase classroom interaction and thus has the potential to improve student's learning. However, current approaches are designed to support specific scenarios and therefore have predefined functional scopes and limitations. This results in lecturers having to adjust their preferred teaching strategy to the currently used system. Hence, our goal is to allow lecturers to customize the system's functionality to their strategy in mind. As a solution, we created a prototype called stARS (scenario-tailored Audience Response System) that builds on top of a uniform metamodel and allows lecturers to create customized teaching scenarios using a graphical editor. First user studies have confirmed that users with different modeling abilities are able to understand the metamodel and use the graphical editor. In order to demonstrate the intuitive use of our prototype, this paper presents concepts to support both the starting phase and modeling of complex scenarios. However, an implementation in real-life scenarios has to be conducted to show its applicability.