When viewing shared PDF files in WebEx, the viewer has the ability to navigate the shared documents independent of the presentation.
Select PDF Document
If more than one PDF document has been uploaded for sharing, you can select the document you want to view from the drop-down menu at the top of the shared file screen.
View PDF Thumbnails
You can get a quick overview of the document being shared by viewing the document “thumbnails.”
On the left-hand side of the screen select the “4-boxes” icon to get a scrolling list of the pages or slides in the file.
Select Specific Page for viewing
Zoom In/Out to magnify the page content