To view thumbnails of all the pages of the PDF, click the THUMBNAILS button in PDFtypewriter.   (If you opted not to view the thumbnails for a particular PDF, you will have to wait until you reopen the PDF or PDF2 to view the thumbnails as they were not loaded into memory.)

The page currently being viewed is highlighted in yellow.

To select a new page to look at, click the thumbnail of that page and the page will be loaded.