In this chapter, we aim to describe the design technology and educational necessity of a smart repository platform, which supports educators with all necessary materials and activities to plan and execute lesson plans, based on computational thinking and STEM activities. To this end, our platform provides guidance and STEM – based lesson plans, functioning as one point of access, where educators provide, as an input, their description about the lesson characteristics (i.e. the learning goals, the activities topics, the didactic approach etc.) and the platform makes all necessary information correlations and outputs the appropriate response to provide lesson plans and activities. For example, a request could be like “Design a lesson plan dedicated to K9 students concerning sports which promotes algorithmic thinking and decomposition”. The quality of the output depends on the quality of the raw input material. Regarding the platform's technology, we exploit a large, ready – made language model (LLM), like Meltemi, in conjunction with the Open WebUI.