When your original laptop screen has been broken, because some reason, e.g press, fall, scratch, so you must get a new screen to replace the old one. But you must know the part number of the screen before you find it, then you can get exact one. If your old screen part number is B156XW02, then you can find on web store by the part# B156XW02.
You can view the following steps for replace laptop screen:
With above, hope you can DIY for your laptop repair.