This guide is just WRONG and useless.
He disconnect the battery cable and nothing else: if you try this, at step 18 you will just pull a flex cable that is still screwed. The correct ribbon is not the one near the battery connector shown in step 10, but the one on the left under the camera.
Guide shows he removes 3 screews, and these are just to disconnect the battery. After this, it is necessary to remove more screws and actually disconnect the display flex: 1 to free the small metal cover blocking the ribbon (similar to step 9) and 8 more screws on the bottom of the phone to free and remove the loudspeaker, which otherwise will block the display ribbon even if it was disconnected and the first screw I mentioned removed.