Wiring problems, and installing new pickups

[Transmissions]

Recently I was given a Douglas 7 string basically for free due to a friends upgrade. The guitar is in okay shape, and I'm complaining because I know it's cheap. But I have a problem, this guitar has some of the shoddiest wiring I've ever seen, the soldering is terrible, and the ground wire is ripped out so it's wrapped around the bridge as a temporary fix.
I ordered a Seymour Duncan JB 7 yesterday, and plan on installing it myself, and rewiring the whole guitar, but I need to know where the ground wire should be to start. does anyone have any wiring diagrams for this Douglas/ideas on what to do about the ground wire?

 

[sage]

The ground wire will usually lead from the solder point on the bridge to the back of one of the pots. Any pot will do. Basically, all of the pots are grounded to one another, the jack is grounded to the pots, the ground from the pickup will lead to the back of a pot somewhere along the line, and all of that will be grounded to the bridge which will take the ground from you touching the strings.

 

[Transmissions]

Thanks, I figured that the wiring was too much of a mess, so I took it to a local shop, and he installed the pickup, rewired the whole guitar, restrung it, set the neck, and filed down the frets for $35
It was just too much of a mess for me to tackle my first time.

 

[HRC51]

$35 for that? Good deal, but try it yourself next time. If it does not work out, you know where you can go for a fix.