In this European multicenter project REACH-Responsive Engagement of the older adults promoting Activity and Customized Health care (REACH), a sensing-monitoring-intervention system is being developed that can be placed in an unobtrusive manner in various care settings and living environments of the older adults. In order to develop such a complex user-centered system, experts from several professions needed to collaborate in a joint development team. To have a successful development progress, it is essential to perform requirement specification and analysis in the beginning of the project. A description of the targeted end-user including the user environment and an analysis of the entities associated with the user and thus associated with the system is needed. Different methods are used to describe and analyze these important components of the REACH system, such as describing use cases, creating personas, developing experience maps, and defining and analyzing stakeholders. The methods used are described and the findings are reported.