Solder the "Hot Wire" from each of your Pickups to the Harness as shown in the diagram. Then solder the "Ground" from your Pickup to the casing of one of the pots (really doesn't matter which one, since they all get grounded). That's it. Your Pickups are connected to the kit (if you are dealing with Pickups with more than a standard 2-wire lead, you may need to refer to your particular Pickup's wiring instructions). Finally, you need to Ground the kit to your guitar. To do this, all you need to do is run a wire from any of the kit's "Ground Spots" (such as the bottom of one of the Pots), to your Guitar's "Master Ground" (usually a Bridge Post or on the Trem's Clawhook.
A Few Special Notes & Tips: Be sure to feed the wires through your guitar prior to making any connections (depending on your guitar, you may also have to disconnect the Switch to feed it through, and re-solder the connections). Also, make "Test Connections" by twisting the wires together, and plug your guitar in to make sure it works before you solder the connections permanently.
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