Download an audio editor program. One freeware program is Audacity. Go to the Audacity website and select "Download Now." Click "Save File" to download the .EXE file.
Install the audio editor. Double-click on the .EXE file and select "Run." Agree to the terms of service, select a destination location, create a desktop icon, and click "Install." Click "Finish" to automatically launch the program.
Add the audio file. Go to the "Project" menu and select "Import Audio." Browse for the audio file and click "Open."
Increase the audio. Go to the "Edit" menu and click "Select > All." Go to the "Effects" option and click "Amplify." Set the amplification volume and click "OK." Go to "File" and select "Save as" to save your work.