Recent investigations of technology-supported learning conducted from an instrumental perspective provide a powerful framework for analyzing the process through which artifacts become conceptual tools and for characterizing the ways students come to understand and implement a tool in solving a task. In this chapter, we focus on instrumentation – the process of transforming an artifact (component/s in the tool) into an instrument that is meaningful and useful to the learners – in the context of statistics education. Our goal is to characterize children’s instrumentation in solving Exploratory Data Analysis (EDA) tasks. To illustrate this process, we bring short episodes from a case study of two fifth graders studying EDA with TinkerPlots in the 2012 Connections project. We suggest three types of instrumentation: unsystematic, systematic, and expanding. We also note that expanding instrumentation is hindered sometimes by instrumented fixation. We conclude by presenting several challenges stemming from the implementation of instrumental theory in the context of learning statistics.