If you know the issue's street address, start by typing that.
If you don't know an exact address, no worries. Just enter an address that will put you in the right general area, and you'll have a chance to refine the location on the next page.
If you have no idea about your issue's street address, enter the town and state. On the next page you'll see a map of the area and you'll be able to drag the issue's marker to the right spot.