Design Thinking (DT) mindset can benefit teachers and students, to help them become active creators and drive innovation, rather than passive consumers. In the classroom, DT has the potential to provide a dynamic process through which pupils can engage in constructionist learning activities situated in real-world challenges, whilst also developing 21st-century skills. However, DT is not common in traditional teacher development courses and the DT mindset should be acquired by the teachers first so that they can cultivate this mindset in their students.

This paper presents the development of an online Design Thinking (DT) toolkit, co-created with teachers to support the implementation of DT in secondary education. The platform uses a "planet metaphor" to represent the four stages of the DT process (Discover, Define, Develop, Deliver), and includes tools like open-ended games to guide students. Two co-design sessions with teachers were held to tailor the toolkit to their needs and test its usability. The result is a customizable toolkit now available for secondary school teachers to adapt for classroom use.

The toolkit is based on another online platform created through an Erasmus+ KA2 project, focused on co-creation in education. The platform was originally designed for higher education to guide students through their DT projects using the "planet metaphor" (representing DT stages as continents on a planet). The platform was and is open-access, open-source, and aimed to support self-learning on DT methodology and mindset for students, especially those from non-design disciplines.The platform did this by providing them with a repository of tools and online material/artifacts including open-ended games that can be used in DT projects. To make DT more understandable, especially for novices in design and students from disciplines other than design, the planet metaphor was used where the DT process is represented as a journey. The continents correspond to four stages of this methodology as described by the British Design Council.

The online DT toolkit presented in this paper aimed to adapt this platform and the planet metaphor for use in secondary education. Teachers' needs were central to the adaptation process, ensuring the toolkit would be practical and relevant for their classroom use. In order to best serve secondary school teachers with the toolkit, and to better understand and meet their needs as the people with lived experience in this case, a co-design process was carried out with a group of teachers.

During the co-design process two online co-design workshops were held with a group of secondary school teachers to ensure the toolkit met their needs. The first session aimed to co-design an online DT toolkit that would guide them through the phases of creating digital-based DT interventions, using the DT methodology in their own classrooms. Teachers suggested tools and resources needed, which were incorporated into the platform. Then, a follow-up session for usability testing was organized for validating, refining, and enhancing the design solutions co-designed during the first workshop. This study reports on the co-design workshop process and presents the main outcomes. Lastly, the online DT toolkit is presented as a platform currently available for secondary school teachers, explaining how this can be adapted for classroom use by teachers.

Keywords: Technology, education.