The answer to 'how to unclog pipe' is to first try using a plunger or a drain snake to clear the clog. If that doesn't work, you may need to use a chemical drain cleaner or disassemble the pipe to manually remove the blockage. However, for severe clogs or if you're not comfortable working with plumbing, it's best to call a professional plumber.
Unclogging pipes can be a messy and potentially dangerous job, so it's important to take the proper safety precautions. Wear gloves and eye protection, and work in a well-ventilated area. Avoid using chemical drain cleaners too frequently, as they can damage pipes over time.