Assuming you are referring to a flywheel with a clutch attached:
The first step is to disconnect the battery. This is because you will be working around the starter motor, and you don't want that accidentally engaging while you're working. Once the battery is disconnected, locate the bolts that hold the flywheel in place. There are usually three or four of them, and they will be located on the perimeter of the flywheel. Use a socket wrench to remove these bolts, being careful not to drop them into the engine (a good way to avoid this is to put a piece of tape over the bolt holes after removing each one). With the bolts removed, gently pry the flywheel off of the crankshaft. It may be stuck on there pretty tightly, so use a little bit of force if necessary. Be careful not to damage either part as you remove it.
Once the flywheel is off, you will see the clutch assembly behind it. The first step in removing this is to disconnect any cables or wires that are attached to it. Then, use a socket wrench or other appropriate tool to remove any nuts or bolts holding it in place (there should be four or five of them). With all fasteners removed, gently pull the clutch plate away fromthe Flywheel . You may needto tap lightly with a rubber mallet if it's stuck on there pretty good. And that's it! You've now successfully removed your car's flywheel and clutch assembly