See STORY 2 in the linked spec

BDD:

Given that I am viewing a Landing Page (with older versions) in view mode,
When I click on the Versions Button in the Studio Toolbar,
Then, the VERSIONS WIDGET appears,
When I hover over an archived piece of content and click on the EDIT button,
Then, I am brought into the EDIT MODE with a new draft of the content that I have selected to edit.
When I click on the PUBLISH button,
Then, a confirmation message appears that my draft is Published and I am brought into the VIEW mode, viewing my published content.