In this chapter, we explore the dimensions of PCK evident in the planning and implementation of an initial modelling practice by an in-service teacher, and how these dimensions are interconnected. To investigate these aspects, we undertook a case study, focusing on the case of Lucy. The qualitative analysis, structured using Trees of Association of Ideas, was underpinned by data derived from audio and video recordings of the lessons in which the planning occurred and Lucy's implementation of the practice with her students. The findings unveiled that PCK dimensions were interlinked through teachers’ interventions during planning, the report of the executed practice, and Lucy's actions in managing the classroom. These outcomes underscore the necessity to enhance new designs for training programmes that foster the integration of teachers’ PCK dimensions.