Organizations conducting global environmental assessments (GEAs) face the challenge of not only producing trustworthy and policy-relevant knowledge but also recruiting and training experts to conduct these GEAs. These experts must acquire the skills and competencies needed to produce knowledge assessments. By adopting an institutional approach, this paper explores IPBES’s epistemic infrastructure that aims to communicate and form the expertise that is needed to conduct its assessments. The empirical material consists of IPBES’s educational material, which teaches new experts how to perform the assessment. The analysis finds three crucial tasks that experts introduced in the assessments are expected to learn and perform. The paper concludes by discussing the broader importance of the findings that organizations that conduct GEAs are not passive intermediaries of knowledge but instead, through their epistemic infrastructure, generate ways to understand and navigate the world, both for those who create and those who receive the assessment report.