How do I get visual voicemail from my keypad? (Samsung S5)

[agdodge4x4]

I just got two new phones, note 4 and S5. I was an iphone user up until now. Anyway, visual voicemail app is set up and working on the S5, but when you push the 'voicemail' button, it CALLS voicemail. I do NOT want that. I want it to simply directly open visual voicemail. My Note 4 works exactly as I described and I had to do nothing special to make that happen.

Why won't this AT&T S5 work without such a hassle? Anyway, how do I force it to link the voicemail button to visual voicemail instead of calling. Google searches have turned up nothing.