I have one, but I don't use it any more. I remember two little black knobs which attach to either side of the bar on the sides of the pram, sort of above the toes of a small baby in the pram. Not the bumper bar, you need to remove that. You have to line up the teeth of the knobs and... I think screw them together. I'm not much help, am I? Am I making any sense at all?? It was DH's job to attach the toddler seat, I'll ask him if he remembers!