How to Get Rid of Ambient Noise in an Audio File using Audacity

How to Get Rid of Ambient Noise in an Audio File using Audacity: "If you’ve ever used a microphone to record your voice using your computer, you’ve likely been irritated by the background noise that is picked up along with your recording. Such background noise mars a recording, making it sound bad and amateurish. Luckily, there’s a way to fix this problem, and it won’t cost you a cent."