If you wish to duplicate one of the pages in your publication you need to perform a couple of easy steps for that.
First, you need to create a blank page where the duplicated content should display
Once the page is created go to the Editor and open the page you wish to duplicate
Left-click somewhere on the page to activate the processes, use Ctrl+A hotkey on Windows (Command ⌘+A on Mac) to select the whole page, then copy the selected content with Ctrl+C (Command ⌘+C)
Finally, go open the newly created blank page and paste your copied content on it using the Ctrl+V (Command ⌘+V) hotkey