New screen ordered from taobao on the right, actually, we could order a plain screen which is even cheaper, but then you have to remove the glue on screen by yourself using a hair dryer. The above contains also the plastic case and it saves some effort.
Fully removed, it contains the battery, which also holds the SIM cards slot. Notice that you should also remove the proximity sensors, the ear piece and the three buttons on the side in case the new screen module does not contain.
It's not very hard after all. Here is a youtube clip showing how to do the disassembly: