I'm pretty new to ArcGIS Online and only have access to an AGO subscription so no ArcMap or Desktop. My question is this: I have an csv file with census tract numbers for a specific county (no addresses). How do I get the longitude and latitude data so that I can map in AOG? I'm assuming that I must join it to a dataset that has this information. How do I join it without ArcMap and Desktop? The idea is to eventually make a choropleth map or potentially a dot density map. Thank you for you assistance!