This report documents a 45-minute solution room session held at the CS4Health Conference 2025 (ETH Zurich, 7 November 2025), organized within the RIECS-Concept project (Horizon Europe, Grant Agreement 101188210). The session used a structured co-design methodology to gather user stories from 25 participants including researchers, patient advocates, clinicians, data scientists, and citizen science practitioners on what a pan-European research infrastructure for citizen science in health should deliver. Analysis of the user stories produced five thematic clusters: (1) a shared European platform with active matchmaking and multilingual support; (2) harmonized data management, federated architectures, and adaptive consent models; (3) ethics and governance frameworks better adapted to active citizen participation; (4) training and capacity building as core infrastructure; and (5) dedicated pathways for meaningful engagement of patients and underserved communities. The findings directly inform the ongoing conceptualization work of the RIECS-Concept consortium.