Thanks. The boards and spine are indeed one piece, as are the "pages." You won't need a lot of tools for this, a torch, saw, square file, and a scribe will do it.
The following holds for both the boards/spine and pages: To get good bends, mark where the corners will be with the scribe. With your saw, cut into the flat of the metal, maybe half its thickness. Then use your file to create a V-shaped channel, being careful to not go through the metal. Then bend the boards or pages.
You'll want to do most of your texturing before bending as the piece is hollow and won't take a hammer blow. To create the pages, I used my scribe and ran it along the length of the unbent pages.
To assemble, fit one U shape into the other, and solder into place.
My original design sketch:
The first time I tried this, I made actual pages out of very, very thin gauge copper. I like this design more.
Good luck, and if you make one, please share it here.