As common learning situations, Problem-Based Learning Situations (PBLS) require accurate template models in which the roles of tutor and learner participate in varied codified cooperative activities. This chapter discusses the use of the UML formalism to first build such customizable models, and next to derive Educational Components (EC) from models. The chapter contributes to reduce the lack of flexibility in “open” learning tools where distribution of components applies with some difficulty. It purposefully introduced the designer role for problem-based learning situations. This designer aims to assemble educational components in order to offer computer-aided learning supports. Model examples and techniques for the implementation of components are also briefly evoked.