The function of the circuit is explained in the PDF file "The Birth of New Technology" starting on page 44, Memo WFC 422 DA. Also refer to Patent #92007861 for the basic schematic. Then cross check all this information with images of the circuit that Don was selling. Take those images and trace down all the circuit pins for the chips. It will take you a few days to traced down all the traces for the IC's. Then build the circuit on a bread board and test it out. Once you feel that the circuit is correct and functioning properly, use Eagle or some other program to make the PCB layout. That simple, but not really, as it will take time to accomplish all this. Its taken me 8 months while working with my group of guys to get this all done.