The VCOFan Makes the blades of the fan audible via light and a light sensor, the light reflects of the blades on the sensor (LDR).
Put the LDR on the front pannel, make it sort of the height of what i did in the picture.
Solder the 2pin header strait up, cut the shringk tube to size if needed, and put it on the LDR. When it is on the LDR you can use your soldering iron to make it shrink around so it wont move anymore.
Mount it all like in the above picture.
Solder the IDC (2x5 male header), then the 2x 100uF capacitors (they have polarity), and the FAN power connector.
Put the rest of the components in.
The LED has polarity, you can see it by looking at where the short leg is (this side goes to ground).
The 2 pin female header connects the top pannel to the circuit PCB (you can see it next to the FAN power connector).
Put in the potmeters and the jack sockets, and screw them all in place.
Check if all it about strait solder, and put on the knobs.
Wind up the fan power cable and `connect it. Then you are done, just the power cable needs to be made. You use a vise to puch the IDC connectors thru the flat cable, look at a eurorack cable you already have and copy it.