Ensure that the existing concrete stoop is clean and free of debris by scrubbing it with a stiff broom.
Lay out the hardwood decking tiles, without connecting them, across the stoop, making a note of where tiles need to be cut. Mark each tile that must be cut with a grease pencil at the proper location.
Cut the hardwood decking tiles with a circular saw equipped with a carbide-tipped saw blade, holding the tiles with the wood side facing up. Take care not to cut through any of the screws securing the wood to the plastic membrane. Rub a high-quality penetrating oil on the cut edges of the wood to reduce the incidence of cracking and splitting.
Lay the hardwood tiles out again, pressing them together to secure the tabs on adjacent tiles. Place reducer strips, available from decking tile suppliers, along the tiles on the outside edges of the stoop to provide a finished look.
Clean the decking tiles occasionally with warm soapy water. Annually, apply a deep penetrating oil sealant to the tiles with an old cloth.