Open the software and "Import" the song you wish to edit by selecting the location or folder. Wait for the file to open, and highlight the song by clicking it. Right-click and select the "Split Track" or "Split Stereo Track" option. The song will split into two tracks, "L" and "R."
Select the music track below the original track; it will be titled "R" or "Right." Select the "Invert" option from the "Effect" menu, and wait for the song to process. Inverting one of the channels will cause the vocals to be cancelled out while still leaving the instruments.
Right-click the "L" and "R" track, and select the "Mono" option for both. Select one at a time if each "Mono" option is in a separate drop-down window. This will give you more control over the pan options in the song.