I've uploaded a FBX of the 3ds Max site model template to Moodle for you to import into UE4; this will help with getting the scale and positions of all the buildings right on the site model.
To use this in UE4 you will need to import it and then scale it up 1000 times (in the x and y dimensions, the z can stay at 1)
Take a look at the import steps here:
Once you've followed those 4 simple steps you'll generate a static mesh, a material and a texture. You can then drag the static mesh into your level and scale it up as above.
The end result will be a very large sheet of A3 paper!