Doors and Windows - replacing old windows

Iam replacing old steel framed windows.The stucco kind of rounds off and the window sits behind it. what is the best way to remove these and replace them.

YOU HAVE TO CUT THEM OUT WITH A SAWZALL,OR CUT THE STUCCO BACK A COUPLE OF INCHES WITH A GRINDER TO REMOVE THE NAILING FLANGE,THEN YOU CAN INSTALL A WOOD BORDER,AND CAP IT WITH ALUMINUM-----EASIEST WAY IS TO REMOVE THE SASHES AND CUT OUT THE JOINING MEMBERS AND USE A "panned"window,measure to the inside of the remaining steel frame,these windows are made with a flared wider exterior flange that will cover the old window frame.on the inside ,you install u-clips,then cut same color metal trim(panning)to size,clip it to the u-clips,and seal--you can call CRYSTAL WINDOWS IN QUEENS,NEW YORK for those type windows,unless you have a closer distributor