Vihara is a paper faced product, meaning that it is installed with the paper facing out.  The paper will be removed during installation.  The FLAT side is the outside of the tile, which is attached to the paper and will be visible after installation.  The BEVELED side is the back of the tile, which will be mounted on the wall.  The purpose of the bevels is to provide more surface area to adhere to the thin set during installation.