Why Did Splitting My PDF Create Multiple Files?

Split PDF creates one new file for every comma-separated range or page number you enter. If you entered "1-3,5,7-9", you'll get three files: one for pages 1-3, one for page 5, and one for pages 7-9 — each downloadable on its own or all at once. If you actually wanted all of those pages combined into a single file, enter them as one continuous range instead (for example, "1-3,5,7-9" would need to become separate steps, or you can merge the resulting files back together afterward using Merge PDF).