Choroplet map from my own geometries

Hi, I’ve successfully ingested my own shape polygon map (US counties) into Foundry, and then into the Ontology. I can make the maps show up in simple map application (see below; which tells me the geometries are ok and recognized), but now I want to make a choroplet visualization in Workshop, and I can’t make it work or even show up. I have a many-to-many Link with places in those counties in the Ontology, and I would like the choroplet map to reflect the sums of places per county. Any suggestions on how to make it work? Thank you.