A bracket is bolted through the insolation and anchored into the concrete block. the bracket is then screwed into the vertical mullions that run through across the rail system. the stone panels themselves are fixed with rivets that get hooked up the horizontal spaning rails and are adjustable (left to right). at the bottom, a grid of pierced aluminum sheet is placed to allow air to flow freely throughout the ventilation space. an outlet at the top allows for the exhaust of air as well as a water barrier.