From their website:
The first is a series of Building Topper Marquees and Letter kits for those that want to dress up their buildings more. They sit best on any of our buildings with a .375" tall or more upper roof edge wall. They sit snugly so they do not need to be glued in place. Some modifications may need to be made depending on what trim and facade pieces have been applied.
The Marquees are laser-cut from Russian birch and the letters from archive safe mat board. They all go together easily using PVA glue commonly known as white school glue.