A: Well, at this point in the season… you don’t. Not really.
Sedgehammer is our favored herbicide to kill nutsedge, and it works well in the lawn and around established woody ornamentals. But Sedgehammer (and every other herbicide that actually kills nutsedge instead of just burning the tops of it for a few weeks) needs three or four weeks of hot and sunny weather to get the job done! This being early October, you’re already too late to have the herbicide reliably work. If you did apply it now, you might dent your population of nutsedge slightly, but not really get noticeable control of the problem.
Reduce excess water throughout the landscape where you can now that temperatures are cooling down. Plan on treating sometime after the middle of May, with a re-treatment for problem areas about four weeks later. The effective nutsedge controls are slow, but they do work when used properly.
But for this year… please just leave the nutsedge be. Pulling it will just give you even more nutsedge sprouts to treat next year.