Alrighty, once you've got Glave's City Meshes downloaded, go to the file that you downloaded, and open it. Inside, you'll find oodles of files.
Find the GLCityMeshes.obj (it should be something along those lines, but it will END with .obj), and copy/paste it into your FeralHeart>>Media>>Objects folder.
Now, take everything else inside the download and copy/paste it into your FeralHeart>>Media>>Objects>>my_objects folder. Replace any doubled files.
Open Map Maker, and you should have Glave's city meshes right there for you to use. c: