To replace pages of your publication with a PDF file, follow these steps:
Click the Edit Settings button of the issue you wish.
Go to the PAGES tab and select the pages you want to replace. Then click the Delete button.
After deleting the pages, hover over the green bubble icon where you want to add the new pages and click Add Page(s) from PDF.
Note: It is possible to add one PDF page at a time. If you plan to add multiple pages, combine them using a third-party tool and upload the combined file.
4. Drag the PDF file to the designated area or browse for it. Click Add pages from uploaded PDF when it is fully loaded.
5. The uploaded pages will appear in a green page container. Click Save and Close when done.