This is the main window of 4Musics MP3 Bitrate Changer where you can add mp3 files for which you want to change the bitrate. You may also see here the OutputFormat and the Tag panels where you can customize settings about your audio file 

In the Program Settings window you may select to delete the file from list after conversion, to delete it from disk or to show only the filemane. You can also acess from here the Preset editor and the Naming panels 

Here you can see how the audio file that you have aded is being converted in the format that you have specified