Is There A Wiring Diagram For Installation Of A Garbage Disposal?

You need to look closely at the wires. The wires are usually coated with a colored plastic covering, or they can have a transparent plastic over them.
 
Black is the hot wire.  A brass screw in a light fixture is the hot connection.
 
The Silver wire is the neutral wire.  Neutral wires are indicated by either of the following:  the wire has ridges; the wire has writing under the clear plastic; the wire has an inner "tracer" line or wire, the wire is white.
 
Your chandelier doesn't "just" have a copper wire and a silver wire but it has a copper wire which is covered with a plastic and a silver wire covered with a plastic.  The color determines whether neutral or hot.
 
Anyway, silver wire is the neutral wire, or as you say, negative.
 
 
 
 

There should of been instructions with it.I could hook up but it hard to explain with out drawing it out for you.I doubt it is code but if I did not know how to connect it.I would go to the hard ware and buy a plug end, that would be a male plug end that plugs into the wall out let.I would connect it to the wires on the disposal,then I would plug into one of those power boards that have all the plug in and a roll switch built in to it.It is normally used for plugging all your computer components in to.that would give you your on off switch for the disposal.