Set Textbox Contents Via actionscript? Super Simple. But how?

Hey all,
I’m just trying to have a textbox on my main stage display certain values depending on what frames are being played. So having not done actionscript in a LONG time, I would assume is it something like this:

textboxvarname = "Value I want to display";

on some frame. but I’m sure I’m way off, cause that doesn’t work! hahaa, thanks