Open the program and import the song you wish to remove vocals from by clicking "File" then "Import" or by dragging and dropping the song into the program window.
Click the pull-down arrow located to the left in the track option field. Select "Split Stereo Track" from the menu. The song will split into two tracks--a "Left" track and "Right" track, which will be located below it.
Click the "Right" track to highlight it then select "Effect" from the menu at the top of the screen. Select "Invert" then wait as the effect is applied. Set the "Left" and Right" track to mono by clicking the pull-down arrow located on the left and selecting "Mono."
Play the song and the vocals should be completely removed.