Select a light kit that will fit your ceiling fan. Universal fit kits are available, but the safest bet for a good fit is to buy one from the same manufacturer as your fan.
Turn off the power to the ceiling fan at the circuit box. Stand on a stepladder or stable stool to comfortably reach the bottom of the fan.
Remove the screws attaching the bottom cover plate to the cylindrical switch housing at the base of the fan. Take off the cover plate and locate the white wire and black wire that power the light kit.
Twist together the bare ends of the black wire from the lighting kit and the black wire from the fan, then twist on a wire nut to secure the connection. Connect the white wires together in the same manner, and tuck the wires into the switch housing. If your kit uses plug attachments instead of wires, plug the pairs of wires together.
Align the base of the light kit with the switch housing and attach them using the cover plate screws. Install the style and wattage of bulbs recommended in your product literature, and then install the lamp globe if your light kit has one. Adjust and tighten spot lights or lamp shades.
Restore the power from the circuit breaker. Turn on the light with the pull cord, toggle switch or remote control.