This paper explores the process of knowledge convergence and knowledge sharing in the context of classroom collaboration in which students do a group learning activity mediated by a generic representation tool. In analysing the transcript of the interactions of a group, we adapt the group cognition method of Stahl and the uptake analysis methodology of Suthers to understand how the members of the group did meaning making in their interactions, and how individual members did uptakes of their interactions and applied their new shared knowledge or understanding in new situations. The transcript is taken from our school-based research using the Group Scribbles software technology which provides representation spaces for individual, group or class work to support collaborative practices. Our work contributes toward a methodology for explaining a process-oriented account of a small group interaction through face-to-face communication over external shared representations.