You can plot the territories by selecting the shape files with supported extensions .shp, .kml, and .geojson. You can also import the CSV file or create CSV file as per the sample file. 
You can download the Sample CSV File and update the details in the CSV file. 
Once you update the details in the CSV file, by importing on the map, it will display the Territory. So you can create and manage the plotted region/area as Territory.