Local governance decisions are shaped by competing priorities, institutional routines, political timing, and community realities. For challenges such as air quality, mobility, or climate adaptation, the core task is understanding the situation well enough to act with clarity, fairness, and legitimacy. A Local Digital Twin becomes meaningful when it is grounded in a specific decision context rather than treated as a general-purpose tool. A well-defined use case provides a clear focus by specifying the decision to be supported, clarifying the forces shaping it, and identifying the knowledge that must be brought together. The co-creation model structures collaboration across phases, helping teams understand what type of work each stage requires and which actors should be involved. Complementary T4R frameworks further support coherence, ensuring the use case remains feasible, aligned, and connected to institutional realities. This learning unit teaches how to design and operationalise use cases for Local Digital Twins. Learners explore how to define decision contexts, map systems and stakeholders, and apply structured stages that keep development focused on real governance needs.