I am using QGIS 3.4.1-Madeira.
I have a base layer map that represents areas as polygons. I have created a CSV file with many entries of different NGO projects, and each one is coded with the ID of the spatial area it takes place. I understand I can't do a simple Join because it only joins one row of the CSV to each area polygon. I have set up a Relation in the Project Properties, which reflects the data structure I want, but I can't figure out how to make it just display in the map as a new layer.