The main window of MP3 Audio Converter displays a panel for selecting audio files or even entire folders to convert and one for the output quality settings. 

Once you've added the file you want to convert, simply press Start Convert. You can also stop the process at any time. 

An interesting feature of MP3 Audio Converter Pro is that you can convert an entire folder and its subfolders containing audio files. 

The Settings window lets you choose the default folder where you want the converted files to be stored and the actions you want the application to take before and after the converting process. 

In the main window you can select the output format from the drop down list shown in this screenshot. 

Once you have decided what the audio format will be, you can now select a sample rate for the converted file. 

In addition to format and sample rate, MP3 Audio Converter Pro gives you the opportunity to choose the bitrate you prefer.