First Person Controller pushing bottons in a quiz.,Making Ethan (FPS) push buttons on play.

Hello! I'm pretty new to Unity and programming in C#. My project is to realize a serious game where FPS Ethan walks through a certain landscape that I created and he goes through some cubes ("is trigger" flag on) and for each cube he collides with, it opens a question ( as a text in the canvas) and its answers (one right and one wrong - as buttons in the canvas - "interactable" flag on). I want Ethan to push the right answer button and than increase a counter to show on video how many object he has collected by answering rightly. So I can't realize the last action. I used a script where using ontriggereevent everytime he collides cube, it shows question and answer, but i don't know how to make ethan push the button and how to handle on click events about button. Please forgive me if it's a very simple question for you all. Thanks to who'll answer ,Hello ! I'm pretty new here, i'm pretty new on coding and using unity. I'm trying to realize a Serious Game where my first person controller(Ethan) has to walk around a certain landscape that i created and in the moment he walks through some cubes placed in the scene, for each cube it will appear a question and also the answers like button to push. I realized everything, but when Ethan goes through the cube( flag "is trigger" on), using an ontriggerEnter, the question and the aswers show up but I can't push the button with Ethan. All the answers are interactable (i checked the flag). I don't know how to push the button and how to make something like deactivate answers and questions when on Click. Thanks to who'll answer :D