Bill, The Free-form date field is just that - you can enter anything you want in the field. If there are dates in the phrase you enter, UFT tries to select a reasonable date from the phrase to use in its Structured and Sort dates. If it can't find a date in the Free-form date field, or if it makes a bad choice, you can set these other two date fields to suit yourself.
I often use a phrase like "from 1953 to 1965" to show a date range. I've even used phrases with no date, such as "at a young age". Whenever I try a new form of Free-form date, I always do a preview in the Event window to see that the event sentence reads nicely. For that last example, the sentence could come out as "He died at a young age". If I have a birth or baptismal date, I could then set the Structured and/or sort date fields to the next year so that it would appear more or less correctly in various displays.