I just realized that after speaking to the person who created the files.
Layer: Administrative boundary (0) and Tables: MEP_global_data.DBO.mep_catalog (1) are linked by a country code column in each.
When I click on the country displayed via leaflet in my browser, I want popup that displays data from the catalog table that is linked to the country via the country code in both the layer and the table. Is their an example that does something similar I can review??
Thanks