FreeRIP MP3 is basically a CD ripper, thus it is a software that can convert audio CD to MP3 or to other audio files (like WMA, WAV, Ogg Vorbis or FLAC). This operation is known as "cd ripping", that's why to access audio CD to MP3 converter mode, you have to run FreeRIP and select View->Ripper menu option.
Once you are in CD Ripper mode, put the Audio CD in your PC CD drive, wait for about 10 seconds to let it spin up, and then click on the File->Refresh CD menu option.
Then select the tracks you want to convert to MP3 and select, from the Rip menu the right option in order to convert them. Example: if you want to convert your cd to mp3 audio tracks, simply select Rip->Rip Selected Tracks to MP3 menu option.
Related resources: Download FreeRIP MP3