In our research, we have been developing a design framework for educational multimedia, based on the cognitive aspects of the users of that information. Design based on "cognitive media" appeals to the particular cognitive aspects of learners, whereas design based on types of "physical media" appeals to particular sensory modalities. This framework informed the design of AlgoNet, a computer science educational hypermedia system that used cognitive media as its basic building blocks. In this paper, we describe a model of student usage and learning with AlgoNet. This model, using the GOMS methodology, provided a useful description of the procedural knowledge required to interact with the AlgoNet system. In addition, our implemented simulations provided estimates of learning and execution times for several instances of the model. Together, the parameters in the simulations and their resulting estimates help clarify the impact of system design, and hence our design framework, on students' browsing and learning strategies.