Open the program and select "Project" from the top menu bar then "Import Audio." Select the folder or destination where the MP3 song is located then press "OK."
Listen to the song by pressing the "Play" button and determine which section(s) of the song you want to edit. Look at the song "Waveform" in the "Track Window" and notice how long waveforms indicate louder sounds in the song and shorter ones are lower. Establish the "Noise Profile" of the song, which are the parts of the song with noise, by selecting a section where there is no talking.
Highlight the noise by dragging the mouse over the area where there is no talking. Select "Effect" from the top menu bar then "Noise Removal." Click the "Get Noise Profile" button then wait as the effect loads.
Select the entire song by holding "Ctrl+A" then select "Effect" from the top menu bar and "Noise Removal". Customize the noise removal to your liking by adjusting the "Less" or "More" slider located at the bottom of the box. Click the "Preview" button, located in the box, to hear the effect. Adjust the slider for "Less" or "More" if you are unsatisfied with the result.
Click the "Remove Noise" button once you are satisfied with the results.