To make a button a link, you'll need to use the 'Link Block' element.
Here's how:
Drag a 'Link Block' element onto the page.
Drag the element you want to make a link onto the page, or skip this step if the element is already there.
Use the 'Layers' tab on the upper-right to drag the element you want to make a link into the Link Block you just added.
Use the 'Layers' tab again to select the Link Block you added. Then go to the Styles tab, the Advanced sub-tab, and expand the Settings accordion. In there, set the URL you want the link to go to.
That's it! Style your inner element as needed.