My matrix is broken, I don't care about it. If yours works and you are not going to replace it - do not touch the display surface (black). Fingerprints are very difficult to remove.

when you lift the matrix, under you will see the motherboard and connected battery. The red circle I marked a power supply piont, which should be disconnected at first. The yellow circle I marked the connection of the digitizer and screen to the motherboard.

the safest way to remove power from the motherboard is separating a power connector. You can do this by slipping a thin non-conductive layer between the power pins (especially the negative ones).