In this paper, we investigate changes occurring in the micro-semiotic activity system of a small publishing house, through mapping the actions of a novice manager in this ecosystem. Using insights from 'situated activity theory' and 'multimodal approaches' to language and action, we begin by examining three levels of organization in this professional activity system, as well as the ways in which they are interrelated : the level of actors' exchanges, the infra-level of actors' individual actions, and the supra- level of the collective activities of the community of practice. The data we analyze consists of ethnographic observations, as well as interviews (ante and post) in the course of which actors are invited to explicit in detail their actions at work. In examining this data, we focus our analysis on : a) the evolution of the exchanges between the novice manager and an old timer mentoring her to help her integrate into the professional community; b) the processes through which the manager typifies knowledge in the course of her trajectory of experiences at work; c) the changes occurring at the level of management culture as a result of the actions and interactions of the novice manager with her mentor, and notably resulting from how she negotiates with him which actions constitute 'relevant practices'; Our findings show that these three levels of organization are both relatively autonomous and independent, yet simultaneously influence each other. This calls in our view for better theorizing not only concerning the 'horizontal processes' of learning which occur at each level of organization but also regarding 'vertical processes' of emergence and downward causation. The analysis also shows the usefulness of an approach to learning taking into account transformation on different scales rather than focusing only on the construction of knowledge at the level of the individual. To conclude, we propose four principles which we see as a basis to conceive systems of learning and professional training. In our view: a) training should be based on the analysis of professional situated activity, b) activity should be conceived as an organized and meaningful system, c) individual, inter- personal and collective learning should be linked, d) training should be conceived as an aid rather than a cognitive prosthesis.