For several years some researches have concerned the process modelling of learning situations integrating digital technologies. Educational Modelling Languages (EML) aim at providing interoperable descriptions of learning scenarios. In order to generalize the use of EML, it is necessary to provide authoring environments allowing users to express their intentions and requirements. This paper presents the core concepts of one of these, called ISiS (Intentions, Strategies, and interactional Situations), a conceptual framework elaborated to structure the design of learning scenarios by teachers-designers. The framework is based on a goal-oriented approach and proposes a specific identification of the intentional, strategic, tactical and operational dimensions of a scenario. This paper also presents how these concepts have been implemented within ScenEdit, a specific authoring environment dedicated to teachers-designers based on the ISiS goal-oriented framework.