From the Landing Pages & Popups dashboard, head to your Popups & Pages List View.
Edit Design or Information
Click into the landing page name or select the Edit button in the right hand column.
Clicking in to any of the wizard headers will allow you to make changes to the page. When you're finished, continue to the publish page and select Publish to close and save.
Duplicate or Delete
From the landing page list view, select the drop down in the right column to quickly duplicate or delete the page.