How to randomly display hidden UI objects in turn?

Hello everyone, I am just learning so far and now I have come to a standstill. And the problem in …


I have a mini project in the form of 2D quiz with the choice of topics. Only 30 topics and in them 7-15 questions in each topic (questions in the style of “guess what’s in the photo” and initially it is not clear what is depicted). Before writing a script, I created all these “questions” in a image format in 2 types (1 photo - question, 2 photos - answer) and temporarily hid them.

And then the question, how:

  1. take into account the selected topics (according to the idea, at least 3 topics should be chosen) that the user chose
  2. How can I choose random 15 questions of all 3 topics or more and in turn “turn on” them on the stage?

The conditions for the transition to the next question may be: the correct answer or the wrong answer is selected or the time for the answer has expired and also at the end of the question “turn on” the image with the correct answer?