This is a Public Library-turned-Birdhouse. What good bird doesn't want to read? There are two Plexi Cut Out Templates included with this download. They show you the size of the plexi you'll need cut for the top and bottom portions with where the doors need to be cut in as well. Basically, 3 mm plexi will need to be cut and slid into the front of the top and bottom with this birdhouse. This will give the two sections security (for the birds) and viewing for the interested humans (which seem to be many).