Clone Section From Existing Group
"Clone section from existing group" will be on the right-hand side of the screen under each of the 4 customize icons. Click on that box and a dropdown with all of the complete groups in your event will appear. You can choose to clone a page from any of the complete groups.
Once you select which group you are cloning, you will be prompted to "Clone and Save" or "Clone and Edit". If you "Clone and Save", you will automatically be brought to the next step in the customization process. For example, if you were customizing the registration page, you will be brought to the itinerary screen. If you "Clone and Edit", you will see the customizable parts of that section change, and then you can edit any elements that you need.