Changing tileset to buildable

Hi all! I use the tileset cityscape, but there are many tiles that's unbuildable! How can i change them all to buildable for my map? It dont have to be easy, cause it's a essential aspect of my map!

You have to edit TerrainData.slk and import it into your map.

you can change what pathing the buildings need in the unit editor too, like undead buildings need blight ect.