Metadata seems to be the most difficult aspect of research data management for researchers to describe in a data management plan, let alone implement in their research. During the "Lunch with the Knowledge Hub: Metadata explained for research data" session on 27 January 2022, we looked at the basics of how (and why) metadata are applied to data for different purposes and for different types of data. We considered practical examples of where metadata are used, and how; and how metadata standards develop and can be implemented. The Knowledge Hub of the Flemish Research Data Network is a network for and by data stewards and research data management professionals supporting researchers. The goal of the Knowledge Hub is to share Research Data Management expertise, practices and tools, and collaborate in training and education. Monthly informative lunch sessions are organised on topics selected by the wider group.