This work draws on the cultural historical activity-theory and the theory of social systems to model socio-technical systems. The concepts of practice, system, and context work as core concepts to represent processes and activities such as learning and working. Current modeling approaches in the field of learning and work resemble the notion of workflows, relating input and output in a means-end-manner and prescribing the processes, and hence fall short in describing the situated and socially mediated nature of practices. Against this background the paper presents and describes an alternative modeling approach as well as its theoretical foundation and practical implications. It is characterized by (1) going beyond de-contextualized actions, objects, and resources and by (2) going beyond the decomposition of activities as it does not equate the sequence of actions with the respective activity.