How to "hardwire" a riding lawn mower?

I received 2 Snapper riding lawn mowers, the parts mower is a "High Vac" and the "good" one looks the same. I'm told everything on it is good, but I need to put it back together. The prior owner replaced the magneto, points and condensor. I'm not sure how to hook up the wiring. I ran a wire from the starter to the + battery, grounded the negative to the frame. It turns over and I have spark. Near the starter is a loose wire that looks to run up behind the flywheel, where should this be hooked up? How do I hook up a "kill switch" so I can turn the mower off? I also overhauled the carb, at first it was flooding the cylinder so I adjusted the float, but how do I properly adjust the float level to get proper air/fuel? Thank you for your help!