Remove the window sash with the broken glass from the window frame. Depending on the window type, you may need to pry off the window’s molding with a pry bar. Set the molding aside so you can replace it when you fix the window.
Remove the screws holding the window sash in place from opposite corners of the window. By leaving diagonal corners in place, it’s easier to keep the window sash corners square when you put it back together again. Set the sash components aside.
Place a small block of wood against the exposed window frame. Gently tap against the wood with a hammer to loosen the frame’s gasket from the window glass.
Pull the gasket away from the broken glass section. You are now ready to insert new insulated glass panels into the gasket and reassemble the window.