Sometimes there will be a dust cap covering the access to the square tapered crank bolt. Unscrew or prize this out.
Unscrew The Bolt/nut
Depending on the fitting of the square tapered crank bolt or nut, use either a socket or hex key to unscrew it. Make sure you remove any washer that’s under the head of the bolt.
Retract The Bolt From The Crank-puller
A crank-puller is a unit that screws into the threads on the inside of the square tapered crank holes. A bolt that runs through it that jams against the axle to force the square tapered crank off the tapered axle. Retract the bolt from the crank puller. Almost all square tapered cranks use the Italian standard 22mm thread but some old French ‘Stronglight’ or ‘T.A.’ cranks need a different crank-puller.
Mount The Crank-puller
Check the threads on the inside of the square tapered crank hole are clean and apply a smear of grease. Screw the crank-puller into the threads, do this carefully as the threads on the aluminium square tapered crank are soft and easily damaged. Finger strength is usually enough.
Remove The Tool And Repeat
Unscrew the tool from thesquare tapered crank arm and repeat the operation on the other side.
Some self extracting cranks have a captive bolt that acts as an extractor. The act of unscrewing the bolt also pulls the square tapered crank off.