Dave,
Since I just did this myself recently, I'll offer my two cents.
The VAL attenuator has "IN", "OUT" and "GND" marked pretty clearly, which makes things much easier, of course. And Left and Right are also pretty clearly identified.
1. The "GND" is the bare wire coming off the RCA input jacks. Just stick the bare wire coming off the RCA jacks with the RED washers and RED-insulated wires on them into the Right GND on the volume attenuator. And of course the bare wire coming off the RCA jacks with BLACK washers and BLACK-insulated wires goes into the Left GND.
2. The RED-insulated wire coming from the input selector switch should be inserted into the Right IN position on the attenuator. The BLACK-insulated wire coming from the input selector switch goes into the Left IN position.
3. By default, the remaining RED and BLACK wires go into the Right OUT and Left OUT positions, respectively.
I would show you pictures of how I did it on my Quickie, but since I changed the layout around, I fear it would be more confusing than helpful. But the above should be enough to make the wiring fairly simple.
Best regards,
Adam