Acrobat Prepare Form Fillable Text Box with Directions that Disappear When User Begins to Type

I have read through the entire thing several times.  As I said, I really didn't understand what they were talking about because I am not versed in html script and dialogue.  I tried implementing Thom's suggestions but he doesn't explain what each lines means and I can't discern whether or not "If" at the beginning of the line is part of the html or he is just beginning his statement sentence, nor do I grasp if all the { } \ / he uses all over the place apply to the formula.  Furthermore, nothing they discuss seems to relate to why the visible instructional text disappears when entering user text but then reverts back to the instructional text after you tab out of the box.  That's what I don't want it to do, is revert back to the instructional text.  I want Instructional Text to be displayed but not print, to disappear when you click on the box or tab into it and for the user entered text to remain and be visible AND printable after tabbing or clicking out of the box.  If you can find that answer in your suggested reading and point it out to me, I would be greatly appreciative.  If not, if someone could answer my query directly, they will have my sincere gratitude.