In vocational education, the learning content is often considered as concrete and specific, and the vocational learning involves physical work and interactions between participants and artefacts. Furthermore, one teacher has the overall responsibility for several students during classes in the vocational workshop at school, which means that the teacher has limited time for every single student and that the few minutes they meet become very important. However, the documented knowledge about how vocational learning is constituted in the vocational classroom and what learning content is focused on in the interaction between teachers and students is very sparse. In this study, we focus on how the enacted object of learning and its critical aspects are made relevant, when a student and teacher in a plumbing workshop session negotiate the conducting of a task in Swedish vocational education. This will be done by using CAVTA (Conversation Analysis and Variation Theory Approach) to make a close and detailed analysis of video recordings of the interaction between the student and teacher when a task is introduced in the workshop session. The results show a complex process, where the teacher alternates between parts and wholeness, using several semiotic resources at hand when highlighting the learning content.