There are also a lot of people making MP3 files when it’s a bad idea. MP3 is a bad format for production. If you plan on opening up a song or show later and edit it, or make an Audio CD, use WAV (Microsoft) instead.
If you need to put a song on your Personal Music Player or send a performance to ACX AudioBook (which demands it), then use MP3, and even then, there are tricks to it.
I installed this link/folder of the “ffmpeg-mac-2.2.2” folder, but when I go to locate this in Audacity, once I try to export audio as an mp3, the actual file that it needs is NOT in that folder that I downloaded.