The answer to 'how to unclog a drain without a plumber' is to try using a plunger or a drain snake/auger. First, try using a plunger to create suction and dislodge the clog. If that doesn't work, you can try using a drain snake or auger to physically break up and remove the clogged material. Be sure to wear gloves and eye protection when working with drain cleaning tools.
If these DIY methods don't successfully clear the clog, it's best to call a professional plumber. They have specialized tools and expertise to safely and effectively clear more stubborn blockages.