Uh, maybe someone else can bullseye which wires are the right ones, but there's supposed to be a short but beefy length of wire with an eye that bolts onto the positive battery terminal, and that wire runs to one of the big terminals of the starter solenoid (which you currently have plugged on to the molex connector for the R/R) and attaches via a spark-plug boot looking thing. That boot should have a second, much smaller wire (white/red) running out of it, through a bullet connector, and then into the wiring harness which eventually connects in to the junction box as a white/red wire on pin 1.
I'm squinting really hard, but I don't see either of the wires that should hook on to the starter solenoid. It's possible those are still attached to the battery/frame? disconnected from the harness at the bullet connector?