I'm not sure what action.Text is, but basically the function I linked draws text onto a sprite you have to supply. (It's actually a little bit more complicated than that: you have to create a DynamicSprite and then grab its DrawingSurface, which is what the function actually draws on.) Then you set that sprite as e.g. a button graphic, a GUI background, a Graphic Overlay, etc. in order to display it. You can see an example in
this thread.
This means, specifically, that if you're currently using a Label to display the text, you'll have to change it a little, since you're rendering a sprite with the text instead. If the text is the only thing on this GUI, I would suggest simply setting the GUI background graphic to this sprite. If there are multiple things on the GUI I would replace the label by a button and set its graphic to the sprite.