Decision-making in the public sector often unfolds through complex sequences of contributions, evidence, and judgments that are not immediately visible. When these processes remain implicit, institutions face challenges in transparency, accountability, and organisational learning. Mapping decision-making processes provides a systematic way to make these dynamics explicit. Mapping connects data, judgment, roles, and behavioural dynamics, revealing how decisions progress from problem recognition to solution approval. Insights from behavioural science help clarify where assumptions, coordination gaps, or biases may influence outcomes. Visual tools (such as diagrams, canvases, and Local Digital Twins) turn these processes into shared representations that support reflection, collaboration, and clearer communication. This learning unit introduces methods for mapping decision-making processes and the tools that enable them. Learners explore how visualisation, structured reasoning, and the Decision Canvas strengthen coherence and transparency, helping institutions document their processes and improve the quality and reliability of public decisions.