Select a character by re-pressing the indicated button until the required character is displayed. Then:
Pressing another button enters that character and moves to entering the next character from the newly selected button.
Pausing for more than a second after pressing a button also enters the current character and moves to entering the next character.
You can select the text entry mode. The current mode is shown by the soft-key label as below. Pressing the soft-key switches text entry to the next mode:
Use the left and right cursor keys to move the cursor.
Press Bksp to delete the character before the cursor.