Yo, this is how to connect the wires to the MIDI ports. Read it
through before starting :)

When you look at the PC EDITOR MIDI Connectors from the back (that
means you're looking at the metal pins, not at the holes), you should see:


 /       \       /       \
| /  |  \ |     | /  |  \ |
| |  |  | |     | |  |  | |
1 4  2  5 3     1 4  2  5 3
  PC  IN          PC OUT

I know the numbers are stupid, but that's the way they are on MIDI
pinouts.

First, drill a hole into the casing to make room for the USB
connector. Be pretty careful with the blue cables, they break pretty
fast (maybe they broke during transport??). Anyway, here is how they
are connected to the USB connector.

When you look at the USB connector from behind (looking at the pins)
you see 4 pins:

   1  2 
   4  3

ON the board, with quartz 6 mhz on upper right, you have four
connectors for cables:

4 3 2 1

That's how they are connected as well. In english (just to be sure :):

utmost left on the board goes to bottom left pin (when looking at pins)
center left on board -> bottom right
center right on board -> upper right
utmost right on board -> upper left

After you have drilled the hole, glue the USB connector the casing
(using 2 component glue, that worked really well for me), cover the
board in tape so that it doesn't short with the metal casing, and tape
the board to the casing as well (like on my picture).

So, you are going to solder the wires onto these pins (just solder
directly onto the pins, I do it by applying quite a lot of solder onto
the pin, then heating it up and pushing the cable into the
blob). There is no need to solder to the Nord board, just onto the
connector pins.

The output of the small USB board (3 black wires) goes onto PC IN, and
the input of the small USB board (1 black wire, 1 red wire) goes onto
PC OUT.

Use the MIDI connection on the right of the USB board when you look at
it from the top (quartz with 6 mhz in the upper right).

The top black wire of the output goes to 5 on PC IN
the middle black wire of the output goes to 2 on PC IN
the bottom black wire of the output goes to 4 on PC IN

That's the way it is soldered to the connector on the board I sent you.

The red wire of the input goes to 5 on PC OUT
The black wire of the output goes to 4 on PC OUT

That's the way it is soldered to the connector on the board as well.

PLug the usb board in, it should get recognized. If not, there is
probably something wrong with the blue cables.

Then test with the editor to see if it can connect. 
If yes -> PERFECT
If no -> check the midi connection, desolder and resolder if necessary.

It gets a bit difficult at times to work in the small casing, just
relax and take your time (sounds easy, doesn't it :)

If you have any questions, feel free to ask me :)