17.
Use the metal ruler to emboss line on both sides of the book.
Curve the corners (the top side of the book) slightly upwards so that they are not completely flat (they will look more natural).
Let the book dry before dusting (I left it to dry overnight, but I might me able to dust it earlier - it all depends on the amount of CMC you added and on the weather - keep on checking the firmness of the paste).