Enabling Next Button once 4 states are visited

I think it's better to use variables and conditions to control the Next button on a menu-type slide. Here's how to do that:

• Create a T/F variable for each slide/topic that will be visited. Set the initial value be False to represent that the user hasn't yet completed the topic.
• On each topic slide, create a trigger that adjusts the corresponding variable to True when the timeline ends. Or add the trigger to the Next button (but be sure it appears before jumping to the next slide). Or, if you're using a custom return button, add it there.
• On the custom Menu slide:
  • Add a trigger to change the state of the Next button to disabled when the timeline starts. Include conditions so it does this if any of the variables are False.
  • Add a trigger to change the state of the Next button to Normal with the conditions that all the variables are True.
    
    • Because there is audio on the Menu timeline that you don't want to repeat on revisiting, do this: Put this trigger on a blank layer, and set the Layer Properties to "Reset to initial state." You'll also need a trigger on the base layer to show that blank layer when the timeline starts.

If you're not familiar with variables and conditions, I highly recommend that you check out Articulate's tutorials and user guides (https://community.articulate.com/articles/tutorials-and-documentation). They provide the real power in the program.