Enabling Custom Next button on completing 4 popup audios

You posted this question also in another thread, please refrain from double posting.

More details are needed. Can you please post a screenshot of the Timeline. I suspect that the introduction audio is of the type 'Slide audio', but I am not sure about the audio for the 'interactivity'? You may be using audio attached to states in a multistate object, or you may use the command 'Play Audio', or you can have used Object audio. Can you please explain?

Depending on your answer the workflow will be different. If you use audio attached to states in a multistate object and the command 'Go to Next State' to play them, you only will need one user variable and an advanced action for the button triggering the change states. If you use Object audio or Play Audio you will need as many variables as you have audio clips and a little bit more complicated advanced action. In any case you need to disable or hide (more user friendly) the Next button with the On Enter action of the slide. 

Another question: do you allow revisiting that slide? If yes, what will the the situation be on another visit? Same as on first visit or not?