Turn off the power at the breaker. Flipping the light switch to off isn't enough.
Remove the screws from your existing light fixture and pull it away from the ceiling.
Cut through the wires to disconnect the fixture. You should cut through three sets of wires — neutral, positive and ground. Cut the wires a couple of inches away from the light fixture, leaving plenty of free wire to connect your new fixture.
Locate the neutral, positive and ground wires on the new fixture. Consult the diagram that came with your light fixture. Ground wires are usually green, neutral wires are white and positives are red or black, but sometimes manufacturers use other colors.
Strip ½ inch of insulation from the ends of the ceiling and fixture wires with the wire strippers. Match the positive wires together. Slip the bare ends of the wire into a wire nut. Tighten the wire nut. Wrap a piece of electrical tape around the wire nut to secure it. Repeat this with the negative and ground wires.
Push all the wire back into the ceiling. Screw the new fixture into place.
Turn on the power by flipping the breaker back to the on position.