Plug in the power auger and position it near the drain. Most models are fitted with a foot-pedal switch, leaving both of your hands free to guide the cable. Feed several feet of cable down the drainpipe. Set the motor for clockwise rotation, then step on the switch to start the cable turning. Push the cable into the pipe until you feel resistance or hear the motor start to bog down. Stop the motor, reverse the rotation and back out a few feet of cable. Switch back to clockwise rotation and feed the cable farther down the pipe. Repeat this back-and-forth procedure until the clog has been cleared away.
Retrieve the cable and flush out the drainpipe by pouring several buckets of hot water down it. If the water still drains sluggishly, run about 2 feet of cable directly down the trap.
Before replacing the clean-out plug, wrap Teflon tape around its threads; this will make it easier to unscrew the plug in the future. Caution: Failure to replace the clean-out plug will allow dangerous sewer gases to seep into the house.