It only needs 7 of the 30 pins, as you can see. Its multilayer PCB, so the tracks to the holes you can see running from the cables go right through with solder.
The 2 next to the striped cable must be left and right, and the striped red connector goes to the whole of the rest and must be the ground.
Check with a multimeter between the cable and the socket. This will ensure the trace is sound.