TIP: Controlling the NEXT Button 101

You don't need triggers to change to Visited or Hover states. Those have built-in functionality. Here's more info: PRIMER: Take advantage of built-in states - Articulate Storyline Discussions - E-Learning Heroes

The icons for closing layers on slide 1.3 don't work because their Initial state is Disabled. That means the program can't recognize when someone hovers over them or clicks them, so they're never changed to Normal. Instead, start them in the Normal state, but don't show them until just before the timeline ends. (Alternately, you could start them Disabled, and trigger them to change to Normal when the timeline ends.) 

There are also some issues with clicking the icons, because the transparent checkmark isn't clickable. Here's more info: TIP: Making icons easier to program and easier to click - Articulate Storyline Discussions - E-Learning Heroes

The triggers that disable Next when the timeline starts would run if a user revisits the slide. They need conditions to prevent that from happening if the user has completed the requirements. For example: 

Note that the conditions are connected with "or" (not "and"). That means the trigger will run if either variable is False. 

You don't need the number variables to track that the layers are viewed. You can enable Next using just the T/F variables.

Note that the conditions are connected with "and" (not "or"). That means the trigger will only run if both variables are True. 

I fixed these issues for the Section 1 content in the attached file. That should help you figure out how to fix the issues for Section 3. 

Good luck!