Turn off the water supply to the faucet. You can find the shut-off valve at the end of each hose line that connects the supply hoses. The football-shaped handles turn clockwise to shut off the water.
Place a bucket under the bottom of the faucet. Flip the jaws of the basin wrench down so they are at 90 degrees perpendicular to the handle. Hold the basin wrench by its T-handle. The curve jaw of the basin wrench should point to your left.
Open the curved jaw with your fingers and position the flat jaw over the nut connector of the supply hose to the faucet stem. Release the curved jaw so the wrench jaws wrap around the nut like a wrench.
Turn the basin wrench handle counterclockwise with the T handle. This loosens and removes the connector nut from the faucet stem. Repeat the process for the nuts securing the faucet to the sink.