The Science Demonstrators play an essential role as early adopters of EOSC from a range of science areas. Their input is used to drive and prioritize the integration of the EOSC services in a common homogeneous platform. To achieve this goal, a selection process for Science Demonstrators through Open Calls has been developed, followed by the execution of two Open Calls. Following five initial pre-selected Science Demonstrators, ten additional Science Demonstrators have been selected through two rounds of scientific and technical review processes. An Engagement Model for Science Demonstrators has been developed and applied. Science Demonstrators have been introduced into their roles, and continuous shepherding of Science Demonstrators during their 12 months project execution has been carried out. Shepherding activities and project progress has been monitored in regular meetings. Feedback was collected in reports which are available for all work packages.