You can extract a specific part out of a PDF document into another PDF. Click Extract PDF on the Tools tab. A new window will open. Click Browse to select the PDF from which the pages will be extracted. You can select one or more page ranges that will form the resulting PDF.

To extract a single continuous range, select Extract from page X to page Y and enter the exact range in the nearby boxes or adjust it using the small arrow buttons.
To extract multiple noncontiguous pages or ranges of pages, select Extract a range and type the page range you want to extract. For example, typing 1, 3, 10-12 will create a new file using pages 1, 3, 10, 11, and 12 of the original.

You can use the built-in PDF viewer to navigate in the PDF.

Click Extract. The original document will not be altered.