Here is some info from the web
on using the Kindle app.

 

 

To download titles your device must be connected to a wireless or data network, but you do not need to connect your device to a wireless or data network to view titles that you have already downloaded.

View all content in your Kindle library:

Tap the Menu icon and then tap All Items.

Switch between content stored in the cloud and on the device:

While in a content library, tap the Cloud and Device option at the bottom of the screen.

Check for recent content:

Tap the Menu icon and then tap Sync.

Remove content from your device:

While in a content library, press and hold an item, and then select the Remove from Device option. This does NOT delete the document from your account – it can be downloaded again later.

Sort content on your home screen:

• Sort by content type:
  Tap the Menu icon to sort content by All Items, Books, Newsstand, Docs, or Collections.
• Filter by title, author, or recent:
  Tap the Sort icon to sort titles by Recent, Title, or Author.

Change the display of your content:

• Display title covers in a grid: Tap the Grid icon.
• Display the title covers in a list: Tap the List icon.

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CLICK HERE to learn more, including how to

• change font/size/etc.
• Add bookmarks
• Change locations in the book
• Explore the book with X-ray [may not work with all documents]
• Add highlights
• Add notes
• Look up words in a dictionary