The answer to 'how to unclog plumbing repair' is to first try using a plunger to dislodge the clog. Wet the plunger and place it firmly over the drain opening, then quickly pull the plunger up and push it down several times. This can often clear minor clogs in sinks, showers, and toilets.
If the plunger doesn't work, you can try using a drain snake or auger to physically break up the clog. Carefully insert the end of the snake into the drain and crank the handle to extend the cable down the pipe. When you feel the clog, twist the snake to break it up. Be sure to follow the manufacturer's instructions and take care not to damage the pipes.