If your display glass is cracked, keep further breakage contained and prevent bodily harm during your repair by taping the glass.

Lay overlapping strips of clear packing tape over the iPad's display until the whole face is covered.

Do your best to follow the rest of the guide as described. However, once the glass is broken, it will likely continue to crack as you work, and you may need to use a metal prying tool to scoop the glass out.