How do you download this as a single PDF document? You have to select every chapter you want included in the generated PDF, but the chapters are split over two

How do you download this as a single PDF document? You have to select every chapter you want included in the generated PDF, but the chapters are split over two pages, and moving to the other page to select all its checkboxes unchecks all the checkboxes on the prior page. There doesn't seem to be a way simultaneously select all the checkboxes on both pages for inclusion in the doc.