There are 3 sockets for the light driver chips as depicted above.
You will need to make sure the chips are oriented properly and that all the pins are safely in the sockets before you press the chip into place.
At the end of each socket there is a large, white marker. In the end of each chip there is a large semi-circular cutout. The mark and cutout must be at the same end of the socket. Note that the orientation is different for each socket.