Wiring question

[Moko]

The manual is great but I can't seem to find where I should solder the last black wire from the 9V batteries.

Looking on Page 19 of the manual in the centre & bottom pics the black lead comes out near 8/9 and then heads down to where it appears to be soldered to the lug 3.

Nowhere I can find in the instructions does it say to solder this wire to 3 ( I can't see from the pic if it is Lower or Upper)

On page 24 the pics seem to show this black lead  being already in place where the two red leads that go to the RCA jacks should be soldered.

So should there be two red & one black lead in the lower part of terminal 3, or just the two red leads & if that's the case where does the mystery black lead go?

I hope you can all tell this is my first go at something like this, and I hope you will put up with my ignorance.

Best wishes


David