Just gonna . . . quote myself. From that comment I left you not a day ago.
This menu uses the id of the building, not the actual ‘name’. So, for the firehall, you’ll be searching for fire_station. EDIT: This has a chance to spawn all possible layouts of the fire station, so you’ll want to increase the weight of your entry (to like 500000) so you can guarantee it’s the one that shows up while you’re testing.
This works for buildings that are only one map tile large (like the fire station). If you’re looking at a building that’s multiple tiles and you want to see them all glued together you’ll have to do as he said above. You can also search the map/teleportation menu using ‘/’.
The overmap editor has instructions above the map legend that are pretty straightforward. EDIT: I actually don’t know how the overmap editor works o_o. So, maybe not as straightforward as I thought.