image click quiz button problem

Hi everyone, I'm quite new on c# and unity, had some experience on appinventor and it was relatively easy for me to manage buttons. I could make buttons act the way i wanted using "if and else statements" with the colorful interface of app inventor but i cannot do the very same thing in unity. The problem is:

I have a button which starts the quiz and plays a random question (mp3 file), then i have some answer buttons which i want to play random okay or alert sound files, one of these answer buttons is correct and the rest wrong. Since the question is random, the answer changes each and every turn. I want to write a script but i cannot. Should i write a script for the start button(start button is at the same time the first question button) or the answer button or the audiosource? I want to do it myself, but unfortunately i can't. I've referred to numerous resources on the internet, and scanned lots of forums but i couldn't find the way out. Can you please guide me, where to focus, what to do and how to do?

Any help is appreciated and thanks in advance.