Download and install the latest version of Lame (Mp3 plugin for Audacity): http://lame.buanzo.org/
Editing your audio files
Open Audacity and load the music track you want to edit:
Click and drag file to Audacity's interface.
Click on File > Open > Select your music track
Use the zoom tool to to get a more precise view of music waveform.
Select the area you want to remove your music (using the selection tool), keeping in mind that you need to select the right connection points ( cue point such as a percussion,.....).
Click on Edit> Delete
Listen to the music track again and check if everything is OK before saving it.
Recording the track
Once the modification made, you need to save your "new" music track.
