Remove the horizontal trap arm that protrudes from the stubout in the wall. Feed the cable into the stubout until you feel resistance. Pull out 18 inches of cable, then tighten the lock screw. Crank the handle in a clockwise direction and push forward at the same time to drive the cable farther into the pipe .
Pull out another 18 inches of cable and repeat the process until you break through the blockage. If the cable bogs down or catches on something, turn the crank counterclockwise and pull back on the auger.
Once the cable is clear, crank and push forward again.
Retrieve the cable and replace the trap arm and trap. Turn on the hot-water faucet to see if the sink drains properly. If it doesn't, don't worry. Debris from the busted-up clog sometimes settles into a loose blockage. Partially fill the sink with hot water and use the plunger to clear the debris. Follow up with more hot water.