I need to take my bicycle crank apart - Cycling

I assume you have a three piece crank (axle plus two crank arms). Go look at the Park Tools website. You will need to remove the little hubcap about the size of a 50 cent piece, then remove the nut on the end of the axle, then use a crank puller to pull the crank off. The crank puller is like a wheel puller in that it has a bold in the middle the pushes against the end of the axle, but instead of having jaws the hook on the outside of the wheel, it has a large male thread that screws into the threads where the hubcap was screwed into. Good luck.