So first, fields with the same names have the same value, so just make the fields you want copied have the same name
For the other bit, unfortunately you have a conundrum. The correct way to display instructional text in a field is with the format event. This event provides an opportunity to change the display of the field without changing the value. But since you've already selected the Date formatting, this option is not available.
There is no way around this if you want to keep the calendar popup.
But if you don't mind loosing it, There is a way around this, but it's tricky. First, you have to set the Custom formatting to override the display on an empty field
// Custom Format Script
if(event.value == "") event.value = "This is my message";
// Custom Keystroke Script
Thank you Thom. That is well beyond my capability. I found an alternative, more cluggy way of accomplishing what I need. It is not elegant, but it works.
What is it?
I left it blank and put in the permanent text field header the need to enter information on another page.