To add a cover to a report, you need to access to the report's configuration,
more specifically to the `Advanced Properties` tab. There, you will find two
checkboxes, one for the front cover and another for the back cover.
They both work the same, so let's focus on the front cover with an example.

* You must check the `Use Front Cover` checkbox to enable the front cover. You
  will see that a new checkbox and a PDF file widget appear.

* If you want the front cover to overlap with the first page of the PDF report,
  you should also check the `Overlap Front Cover` checkbox. Leave it unchecked
  if you don't want the front cover to overlap with the first page.

* The last step would be to upload the PDF file that will be used as the front
  cover. You can do this by clicking on the PDF file widget and selecting the
  file.

* Important! The file must be a PDF file, and it should have only one page. If
  it has more pages, only the first one will be used.
