Patrick Stewart has made a very nice video of how it works. Click Here
If you would like to try this software there is a video and a free trial version available at singingcoach.com
This software works best on a PC (see the System Requirement of the trial download page) but can be made to work (although it may be slow) on a Mac with Windows emulator software which will be much more expensive and tricky.
To download these files, RIGHT-CLICK them and select "Download linked file…" (or some variation of that). If you simply click on the links they won't download and you won't be able to use them with Singing Coach.
If you have questions or need help, contact Geoff.