Cut power to the existing ceiling fixture, at the house fuse box. Remove the existing fixture by extracting the screws holding it to the ceiling, lowering it, then disconnecting the wires above it. Leave the wires from the house circuit hanging down from the exposed electrical box.
Install the mounting bracket from the Harbor Breeze fan kit onto the electrical box, using the machine screws that came with the bracket. Connect the bare grounding wire from the box around the green screw on the bracket. Let the other wires (generally, one black and one white) hang down through the opening in the bracket.
Take your fan unit up the ladder (without the blades attached yet) and hang it from the small hook on the bracket.
Wire the fan by attaching like-colored wires (white to white, black to black) from the box to the fan. Make each connection by holding the wire ends next to each other and twisting on a wire nut.
Lift the fan unit up to the ceiling, lining up the screw holes between the fan unit and the mounting bracket and inserting the provided screws.
Attach the fan blades with the screws that came with the kit. Turn the power back on.