Interactive video - navigate in the playbar to replay a section

To start, I would add in some True/False variables, one for each Question layer. Then add in a trigger on each question that changes the trigger to true when the user hits the validate button on the question. Then on the main base layer, I would change the trigger to Show layer Q1 if Variable is not equal to true. That way when you go back through, if the questions have been visited and the variable is true, the question layers won't launch.