Don,
I haven't used the Melodist feature so I'm not familiar with its options or how to use it. However the description available in the manual starting at page 300 or by pressing the Help button appears to describe what each option does pretty well.
There is a 15 minute video covering both the Soloist and Melodist features
+++ HERE +++. The video is located in the Archive video section.
An easy way to find any specific video is to navigate to the page, press Ctrl + F and enter a search term. In this case I entered the term "Melodist" without the quotes. The up arrow and down arrow next to the search box act as previous / next buttons that will navigate between occurrences of the search term.
Hope this helps.