Variables with conditions

Try the attached sample, which allows the items to be visited in any order.  If you don't use a custom Next button, you will need to do as Jackie suggests and use a trigger at the beginning to disable Next.

Here's a sample of how to do it. You insert a shape (smiley face) and set it's state to "Hidden". Then you add a trigger to change it's state to normal when the user hovers over the button. You do this for each button that the user hovers over. You add a trigger that says change the state of the NEXT button to normal when the state of (ALL) smiley faces are normal.

Cheers!

Are you using the Continue button that is included with Walt's example? If so, then the trigger you need to create is "Jump to slide next slide when the user clicks Text Box 1" (Text Box 1 may be named something else if you renamed it).
Otherwise, you will need a trigger that looks something like this:

I tried to come up with a solution for hover, but it seems to require too many triggers.

What you can do is have one trigger that changes the state of the Next button to Disabled when the timeline starts on the slide. And then have another trigger that changes the state of the Next button to Normal when the state of all of your items is Visited. Instead of just hover, the user will have to click on each item, but this should work.

This is all very helpful and got everything working according to Walt's triggers, but im stuck on getting it to go to the next slide.  I disabled the next button when timeline begins, but now i'm struggling: I added change state of the next button to normal when all 4 states are visit (when timeline begins?) but it wont go to the next slide.