[sdiy] Paia Ekx10 ADSR questions

[Prototek]

    My friend recently gave me an old Paia Ekx-10 ADSR kit. Its based around
a CEM 3310 chip. I had no problem assembling the board, but I'm a bit
baffled as to how to wire it up to the panel.
    On the lower part of the board there is a row of pads that I assume are
for the jacks but I'm not 100% sure. There are also single pads spaced
around the board with the letters A, B, C, L. They are reffered to as
"summing nodes." I have NO CLUE what this means. I only hve experience in
assembling MOTM kits which are known for there "fool-proof" instructions, so
you can imagine this little Paia is confusing me a bit. Can anyone shed some
light on this and/or maybe give me an idea what the front panel should even
look like?

                        Thanks,
                        John