To find Latitude and Longitude the desired geographical point you can use any site is an online geographic tool. We recommend Latlong.net site that can be used to look up lat long of a place and get its coordinates on map.
You can search for a place using a city's or town's name, as well as the name of special places, and the found latitude longitude will be shown on the right side of the page. At that, the found place will be displayed with the point marker centered on map.
Finally go to Appearence > Zoner options > Maps and enter the received data.