Oscar's mouse hacks come with pin headers where the gray wires are soldered to the board.
From there you run wires to the header for the trackball end of things.
The optic boards, and gray wire that you have with that are not part of Oscar's standard mouse hack.
To get it running, you need to cut the optic boards off the mouse hack, and run the wires to your trackball.
There will be a +5v, a gnd, and two colored wires that run to each optic card on the trackball.
If your axis comes out swapped in Windows, reverse the two colored wires.