[Zubersoft]

The first thing you need to do is figure out where you've placed the PDF files you want to import. A typical place for downloaded files to go is /sdcard/downloads. For reference, the paths /storage/sdcard0, /storage/emulated/0, and /sdcard all point the same place on the SD card.

How are you getting the PDF files on your tablet? Are you downloading them from the web or transferring from your PC?

Mike