This chapter explains what CDA is and how it can be used as a tool for analyzing social media data. It begins by providing an overview of the nature of CDA and how it can be applied. It explains how CDA is a kind of detective work, where we look closely at the details in language and grammar to reveal the subtle meanings that can be communicated and that may be less obvious to the casual observer. Using examples from social media, the main concepts and principles of CDA are explained. Some of the basic tools of CDA are then illustrated using a number of examples, in particular the importance of focusing on how participants, actions, and causalities are represented in language. This approach allows us to draw to the surface some of the ideas, values, and meanings that may otherwise not necessarily be overt. The chapter then goes on to show how to use CDA for a specific research project. It shows how this means asking clear research questions, engaging with the wider literature on the topic. It looks at how to sample data, how to analyze this, and finally how to draw conclusions in relation to the research literature, showing how to reflect on what contribution the research project has made.