Home key 
— takes you to the Home screen which lists all of the reading material you have on your Kindle.
Text key 
— allows you to change the size of the text while you are reading. Press the text key and use the select wheel to choose a different text size.
Tip: You can only adjust the text size in reading material. You cannot adjust the text size in Home, the Kindle Store, etc.
Search key 
— shows or hides the Search text entry box for submitting a word or phrase to search for.
Symbol key 
— shows the Symbol menu for selecting characters not shown on the Kindle keyboard.
1.3 Entering Text
To use the Kindle keyboard, most people find it easiest to hold the device in both hands, and use the tips of their thumbs to press the keys.