First turn off the water to the rig.
If it's a single lever faucet.
Under the lever, you'll see a little plastic button, remove it. You'll need a hex Allen wrench to remove the hex lock screw in that little hole. Take off the lever and you'll need to figure out what needs to be removed next to take out the valves inner workings. Keep an eye out for O-rings and where they go when putting it all back together. Different brands are a little different on the inside but still easy enough to figure out. Use plumbers lube when assembling for a longer lasting smoother operating faucet.