Button States: States for some buttons not changing when button is clicked

You're doing way more work than you need to. 

You don't need to use Groups for buttons. In fact, I recommend against that, because it usually causes problems.

Instead, insert the icons while editing the states of the button shapes. Here's more info about that: TIP: Making icons easier to program and easier to click - Articulate Storyline Discussions - E-Learning Heroes 

Here's how to control the buttons:

• Instead of your "Home" state, give each button a Selected state and a Visited state.
• Put the buttons into a button set. That makes them act like the radio buttons in a multiple-choice question. Clicking one automatically deselects the previously selected one. 

Here's more info about using built-in states: PRIMER: Take advantage of built-in states - Articulate Storyline Discussions - E-Learning Heroes

You can control the NEXT button via checking that the buttons have all been Visited. Here's more about how to do that: TIP: Controlling the NEXT Button 101 - Articulate Storyline Discussions - E-Learning Heroes

• IMHO, you shouldn't force users to click every button for this slide. Users probably know what each button will do or are comfortable enough to figure it out. In fact, unless they're computer neophytes, I wouldn't even put that slide within the content. I'd add a Help tab in the Player that lightboxes the slide. Then it'd be accessible at any time for those who need it, but it wouldn't bother those who don't. Here's more about adding Player tabs: https://community.articulate.com/discussions/articulate-storyline/tip-create-custom-player-tabs-for-your-resources-glossary-and-more