Loriel, there is no pivot on the floor, they are hung just like a regular door, the hinges are on the door jamb just like your front door is.
Willie, we used magnetic catches to hold each door against the door stop and on some I have installed we used the ball catches in the header piece of the jambs. When opening the doors they will swing into the room if you don't fold them up as they are opened. I have seen where the two clips that are used on the bottom back on regular bi-folds, to keep the bottoms aligned, used with this type bi-fold. I never did like them because they rubbed the backs of the doors.