Our work is situated in the context of TEL (Technology Enhanced Learning) research. It concerns more particularly the instrumented educational design and scenarisation field. In this context, our research problem was the expression modalities of learning scenarios which would allow a scenario to be easily reusable by teachers and educational designers. Our research methodology is based on a double approach: a modelling approach and a user centered approach. It aims at the elaboration of theoretical models in interaction with the educational practitioners and it integrates evaluations at the different modelling stages. We present in this article two additional researches: an exploratory research on formalisms for the expression of the scenarios which led to us to the construction of a method, the method of Pleiads, which allows the explicitation of the teachers’ intentions and facilitates the learning scenario transferability.