MARK OUT WHERE YOU WANT YOUR OPENING, ON ONE SIDE OFF WALL,CHECK WITH MULTI SENSOR FOR WIRES,PLUMING E.C.T. IF YOU DONT HAVE ONE KNOCK HOLE IN CENTER WITH HAMMER. I.E.30CM BY 30CM.ON SAME SIDE GET A TORCH. CHECK FOR WIRES E.C.T. VERTICAL TIMBERS SHOULD BE 62.5CM APART . CUT LEFT OR RIGHT MARK...