When installing the Fundo Riolito trap below the base you must first locate your drain pipe. If working on concrete you will want to trace the area of the drain trap, and begin chiseling and cutting away the concrete approximately 1“ below the concrete surface. If you are working with a wood substrate, simply trace the trap template positioned (squarely) at the drain position provided and cut your plywood to allow the trap to slide into the wood substrate. Your plumbing pipe should be cut 1 1/4“ below the top of the subfloor. Once the plumbing has been dry -fitted, the drain pipe is ready to be solvent cement glued to the trap using appropriate cements. Finish installing the trap but do not use wedi joint sealant around the perimeter, and use no screws if installing over plywood, to fix the trap. Take care of securing the trap units solid support so it cannot move under water load or otherwise. Fill the drain and trough with water to ensure proper connection, do this immediately after setting the base in thinset to allow for quick adjustments if needed. NEVER walk or stomp the drain area into thinset bed. Instead, gently push in place. Ensure the drain section is fully supported by floor and thinset mortar bed. Any voids will add tension to the drain which might lead to cracks.