The Every1 project has developed a large, openly licensed collection of learning materials to support citizens and professionals engaging with Europe’s digitally mediated energy transitions. The project adopted an iterative methodology that combined a cyclical production pipeline, embedded co-creation, and multimodal user testing across six development cycles. Stakeholders from fourteen countries contributed through interviews, workshops, surveys, webinars and roadshow activities, generating insights that shaped both the content of the learning materials and the design process. Findings highlight the value of relational engagement, linguistic and contextual localisation, and of offering a diverse portfolio of materials to meet varied learner needs. The resulting Every1 Model provides a transferable framework for co-creating open learning materials in complex sociotechnical domains. While the learning materials consistently improved understanding, the evaluation findings revealed a persistent gap in behavioural activation, indicating the need for future work that integrates motivational and structural factors. The model also contributes to wider debates on digital learning design, public engagement and the role of openness in supporting equitable energy transitions.