A method for assembling a seating system by providing a base member and pad filled with fluid. The pad has a front, rear, and sides with the sides flaring outwardly of each other and of a center axis. The pad further includes an arcuate, transverse seal extending substantially from side to side across the pad and opening to face toward the front of the pad. In the method, the pad is gathered into pleats by bringing the sides toward each other until the arcuate seal assumes a substantially straight line and then positioned in its gathered state over the base member.