Industry 4.0 seeks both to digitalize SMEs and to bring companies closer to their market. One of the responses is the Do-it-together (DIT) concept, which combines co-creation, and open-manufacturing. This concept is transposed in the form of a physical and digital INEDIT demonstrator (EU project). This study analyses the design modalities of multimodal interfaces and multi-platform (web app, AR mobile app, VR app) supporting the DIT process. The study focuses on the realization of an original UX design protocol allowing to design and evaluate by use this potential "multi-sided" platform. The results allow us to better understand the modalities of implementation of such an approach mixing Action Research and Living Lab for industry. We can appreciate over time the commitment of the stakeholders and their ability to co-create such a platform. This work allows us to draw recommendations for the development of support technologies for socialmanufacturing and provides argument for a Multi-UX scale.