Computer simulations is a resource that can act as a kind of pivot, among others, to obtain different configurations of practical work: Virtual Lab work, Simulations-based practical work, lab work, experimental work and field work. Instrumental orchestration is a theoretical framework that gives the support to articulate the different resources and design the necessary teaching approach to take advantage of their use in terms of student learning. An important point of this theoretical approach is that it allows a connection to be made with the development of students’ epistemic practices. The different configurations that we can use the computer simulations will be presented with concrete examples of its use in Physics and Chemistry teaching. Also, we present the results of its impact in terms of student learning. These results will be interpreted in light of the instrumental orchestration. The main conclusion is that the appropriate use of computer simulations is effective in terms of students’ learning. However, it is not irrelevant how the simulations are orchestrated in terms of the articulation among resources, the teacher's mediation and the time dedicated by student’s use of the resources.