Computational thinking (CT) is a set of problem-solving methods which several scholars advocate for its inclusion in the educational curricula for K-12. Incorporating this knowledge into existing syllabuses is a challenge for both the educational community and researchers within the field of STEM education. The focus of this study is on the importance of co-design and constructionism in the process of planning and designing teaching modules to introduce students to CT using both robotic constructions and programming. This paper presents and discusses the design process of a series of workshops conducted with a group of middle school students during the fall of 2020. The main goal of these workshops was to introduce students to the main concepts and practices of CT, thus addressing the goals defined by the Swedish Agency for Education (Skolverket). Our initial findings indicate that co-designing educational activities (with a focus on constructionism and challenge-based learning) in close collaboration between teachers and researchers can lead to effective ways to foster the development of CT skills among students.