How do I make a GUI Text Box have a display condition?

Hello! For my mod, I have a GUI where a player needs to enter an item id to get a villager trade. I think I have most of it down, but the text box in my GUI is only supposed to appear when the player clicks another button first. When I make or edit the GUI text box, there is no place where I can add a display condition. I was thinking of adding some custom code, but I have no idea how to do that. Can anyone help?