The best way to wire up the Stern Sound Board to the J5 connector is find pin 1 of the connector on the sound board and plug that into Pin 1 of the MPU board.  Than repeat this process for the next connector which will be pin 17 to pin 17 on the MPU board.  When your completed, you will have 2 spare pins on the far left on J5 MPU board which are used on some very rare games.