SD Card

This device has an SD card slot, and there is a 32GB SD card in the slot - but nothing is using it.

In the file system I have:

• Root
• extsd  
• sdcard
• etc

EXTSD is the external (32GB) sd card.  SDCARD is internal storage.  In Settings\Storage I have:

External SD card:  29.71GB total / 29.71 GB available
NAND memory:  6.69GB Total / 6.29GB available

Files, eg applications installed to SD, Kindle eBooks etc are going to the NAND memory (which is sdcard) in the file system.

So how does this work?  And how can I make use of the 32GB SD card?