There will be a breaker to kill the power. Shut it off first. Next, at the top of the fan there is a round metal skirt covering the base. It should have four small screws. Remove them, next let it drop down. Then you will see four wires, a blue one,a black one,a white one and a solid copper ground wire. Pull them out gently. Untwist the wire nuts on them and sepperate the wires. Now all you have to do is lift up and forward on the fan and the ball it rest on will be out. Now just set it down..if you don't have another fan or light to replace it with then

where the chain goes into the motor there's like a metal coupling, you should be able to twist it off and find the end of the chain-you can attach new chain with one of those little ball chain joiners and screw the coupling back