Fitting a new handlebar casting

I HAVE A VESPA PX 125 WITH DISK BRAKE AND I WANT TO REMOVE THE HANDLEBAR CASTING BECAUSE IT IS DAMAGED.CAN ANYONE TELL ME THE STEPS TO REMOVE IT AND FITTING A NEW ONE.

Too long an explanation, but totally basic, best bet here would be get yourself a haynes manual. Just a case of remove everything swap castings and put it all back. Additions to it all from personal experience, Flush thru brake fliud (obviously whilst bleeding brake but make sure runs clean), Minimun, replace inner cables, preferably complete nylon lined cables. Just do it and youll work it through, get on the board with any hiccups