Deleting, Rotating, and Exporting pages within a document
2. Select Thumbnails
3. Enable Selection by clicking on the Select button
4. Check boxes will appear on all the pages, and tapping or clicking on a page will now select it.
5. Select one of the options to Rotate, Delete, or Export the selected pages.
Tip: If using mouse, you can also right click on any page to perform any of the above actions. This will only affect the page that was right clicked though.
See also:
Merging PDFs, Images, and adding blank pages to existing PDFs
Reordering pages within a document