How to add a next button.

Hello,

On one of my slides I have added three layers, on those three layers (its kind of like a menu page) I added a hover and a visited state. Now, I am using a trigger to add a 'next' button on that slide. But, I only want the user to be able to click next when they have visited all the three layers.

Could you please help me add the next button, with those conditions?