I'm not completely sure why you needed help on this particular issue. This is an extremely easy task to accomplish. But, since you asked, this is all it takes:
1 - Add an action to the player using the "Is overlapping another object" event and set the text to visible.
2 - Add an else event right after the first with no other conditions. An else event triggers any time the previous event in the list would not trigger. Give this event an action to set the text to invisible.
I am including a capx just in case this isn't clear enough.
Good luck with your project.