Follow each step carefully.
Identify the display flex cable on the logic board.
Carefully align the display flex cable connector with the socket on the logic board.
Gently press down on the display flex cable until it clicks into the socket.
Identify the ambient light sensor flex cable near the display flex cable.
Carefully align the ambient light sensor flex cable connector with its socket.
Gently press down on the ambient light sensor flex cable until it clicks into the socket.