This will get you up and running with the Audacity sound editor, a very capable and historied GPLed sound editor. Begin by downloading and installing Audacity. The installer for Audacity itself is pretty clean and informative. If you can, leave everything at the default — this will ensure everything works when we’re done.
Follow that up by downloading the current binary version of LAME. Some notes: because of intellectual property rights run amok you can’t download a copy of binary LAME from their website. The installer can only be downloaded from websites hosted in countries that don’t have the same level of protectionism. When you go to download Audacity, you’ll actually be directed to http://lame.buanzo.org/#lamewindl. This is fine. If you’re nervous about downloading from this particular website do the research and find another that you’re more comfortable with.
On the #lamewindl page hosted on the buanzo.org website you’ll see a header entitled TO DOWNLOAD Lame and FFmpeg for Windows, click links BELOW: The installer you want is linked below this header and labeled as the RECOMMENDED Installer Package for Windows. Run the installer, leave everything at the default value.
If you installed everything into their default locations you should be able to run Audacity and find everything in place to import and export MP3 files, as well as other sound formats.
A note on MP3s: MP3s are compressed sound. That means that bits of information have been left off the MP3 file in order to conserve space. Normally a person won’t object to the difference between an uncompressed music file and an MP3. If you compress an MP3 again, however, the noise will be very noticeable. It’s best to always input from uncompressed audio and output to the needed format.
That’s it. To be honest I thought this would be more work but we’re done.