Thank you for your question. To remove your cartridge first shut off the water to the faucet. Next, underneath the blue/red button on the handle there is a set screw, loosen the screw enough to take the handle off. Make sure you don't lose the screw down the drain. Once the handle is lifted off there will be a cap underneath. Unscrew the cap. You now should be able to remove and replace the cartridge and reassemble the faucet.