PLAINFIELD – Amazon representatives this week gave the clearest picture so far of how a proposed company distribution warehouse planned for construction on the former dog track property will operate. During Tuesday’s Planning and Zoning Commission meeting, Jessica Schumer, an economic development manager for Amazon, gave members a “day in the life” look at how the “last-mile” facility will run. “’Last-mile’ is a bit of a misnomer, but it is the last step a package takes before arriving at a customer’s door,” she said. Schumer said for 10 months of the year, approximately 30, 18-wheelers would arrive at the Lathrop Road facility during the overnight hours – more during peak holiday months –and start unloading packages ordered by customers’ smartphones and computer screens. Such orders typically get delivered via the U.S. Post Office, UPS or the “last-mile” option.