Most faucet kits, such as those made by Kohler, come with pop-up drain stoppers and the parts needed to make them work. A push lever in the faucet handle connects to the stopper lever below the sink by means of a spring clip. Pushing down on the handle in the sink causes the stopper lever to rise. You can adjust the pop-up drain on a Kohler to get your stopper at the right level.
Turn off the sink if water is currently running. There is no need, however, to turn off the water supply to the sink.
Remove any objects stored beneath the sink and around the drain area to give yourself room to work in.
Take a flashlight and use it to locate the point where the horizontal stopper lever coming out of the tailpiece meets the vertical pull lever in the sink above.
Squeeze the ends of the spring clip together where the two metal rods meet. Slide the spring clip and the push lever away from you and towards the wall until they come off the stopper lever. Use the pliers to help you squeeze the clip, if needed.
Adjust the pull lever in the sink above until it is at a comfortable angle. Secure in place with a piece of masking tape or duct tape.
Locate the nearest hole on the push lever that lines up with the stopper lever. Slide one end of the spring clip over the end of the stopper lever then do the same for the push lever and finish with the other end of the spring clip. Squeeze the spring clip together as you slide it over the stopper lever. Release when the push lever has been attached.
Raise and lower the push lever in the sink above and check that it operates the stopper properly. Make further adjustments if needed.