Next , attach the two smaller sides together with the long stretchers the same way ., add the leg supports and centre supports . Once the base is assembled , add your decorative slat wood boards to the outside using wood glue and nail gun nails . Seal the wood with an outdoor polyurethane . De-mould the concrete slab and lightly sanded the edges by hand , before sealing the concrete . Last step is to assemble the table and insert the pan into the opening . You can also drill drainage holes into the pan for easier cleanup .