Procedure
1.When you are in a file, press EDIT to select the edit mode.
2.The blinking cursor indicates where you can add a character. You can delete characters in the edit mode and add new characters in their places.
3.When you type in a character, it is inserted above the cursor. Then, the cursor automatically moves one place to the right. To
replace a character above the cursor, press DELETE. The, type in the new character.
4.You move the blinking cursor to the
left or right by using the 
(right) or 
(left) arrow key.
NOTE: When the message is too long to fit on the screen, small arrowheads appear at either end or both ends to show you that more characters are off the screen. 
Arrowhead tells you more characters are to the right side of the screen. 
Arrowhead tells you more characters are to the left side of the screen. Use the right and left arrow keys to scroll back and forth to reach any part of the message for viewing and editing.
5.When you finish editing, press ENTER to store editing changes.
6.If you want to stop editing at any time, press QUIT.
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