You can create WAVE files by simply pressing "To WAV" button. 

To set the parameters of WAVE files, click "Settings" on the main menu and then click "WAV settings".

The software will store the information of the files to be converted in the Play-List (In the Play-List only MP3 or OGG or WMA files will be stored). Then the files will be converted to WAVE automatically unless you press "Stop" or "Quit" button. The converted files will be stored in the folder you have selected in Output directory.