You can add second button with jQuery.
Go to your Dashboard → Settings → Insert Headers and Footers → add the following code to Scripts in Header section, and click Save button:
jQuery('a.roll-button.button-slider').after(jQuery('<a href="2ndButtonLink" class="roll-button button-slider">2ndButtonName</a>'));
2ndButtonName with desirable values.
Also you might want to add some space between buttons with the following CSS code:
You can add CSS code in Dashboard → Appearance → Customize → Additional CSS (WordPress 4.7 and up). Also you can add CSS code directly to
style.css file of your child theme.
Please feel free to ask any other questions that you might have.
Kind Regards, Roman.