From the main dashboard page select 'Manage pages'

Find the section menu you want to edit and agian click 'Manage pages'

To add a new list page click 'Add new page' the slide out page options should appear.

Find the 'PDF List' option (note that this is different from a single PDF page)

Fill out the title and select an icon if required and click 'Submit'

This will return you to the section menu, to add a PDF into this new list click the 'View' button on the PDF List.

Click 'Add PDF' and fill out the title and upload your file.