This deliverable (Deliverable D5.1) defines the conceptual and operational foundations for the preliminary user studies within Work Package 5 (WP5) of the PlaceMUS XR project. As a foundational report (M4), Deliverable D5.1 focuses on establishing a rigorous methodology and a suite of research tools designed to inform the subsequent design and development of sound and visual based immersive experiences. The methodology is grounded in the PACT framework (People, Activities, Contexts, Technologies). A mixed-methods strategy is presented, centred on a set of structured, multi-target questionnaires designed for six key stakeholder groups: Consortium Partners, Researchers, Museum Curators, Educators and Students, Cultural and Creative Industries (CCIs), and the General Public (Visitors, Citizens and Tourists). These tools have been developed to capture both transversal trends (Common Core) and role-specific requirements (Target-specific sections), with an emphasis on Universal Design and Accessibility. In accordance with the project’s timeline, Deliverable D5.1 presents the survey instruments and the Data Collection Plan (M5-M16). The results of these studies will directly inform the system specifications for the VR Mockup Tool and the overarching PlaceMUS XR model. All activities are designed in full compliance with GDPR and ethical guidelines, ensuring data minimization, informed consent, and secure management. As a methodology-oriented report, Deliverable D5.1 provides the systematic and transparent research baseline necessary to ensure that the PlaceMUS XR digital ecosystem is evidence-based, user-centered, and scientifically validated within the European Collaborative Cultural Heritage Cloud (ECCCH) framework.