How can I add a new location/city/municipality to MSS 6.3.1

I thought that I could just add a new location, but when I select the correct province, the city name field becomes available and the city/town doesn't exist in MSS. Maybe there is a way for me to add this location. It seems to be, basically, a one intersection town in rural Manitoba.

If there is another place that I can add information, please let me know.