Install the flashing by sliding it into place, so that it is sitting under the tiles above it. Run a bead of silicone on the two tiles next to the flashing. Use the mallet to gently tap down the sides of the flashing, so that it follows the profile of the tiles. With your hands, roll the front edge of the flashing, to form a lip. This gives the flashing more water protection. Make sure you're wearing gloves when working with the flashing because it has sharp edges.