First one will show you a list of predefined answers (you can edit them at menu)for fast reply. Only tap one of them and it will be written\n\nThird one will cipher your message. Write your message and tap on this bubble in order to cipher it. If you have more than one password you will see a list. Select the one you share your your friend.\n\nThe second one is for deciphering the messages you are watching in your screen at this moment. The App will use all your passwords in order to decipher the message. If it is not able to decipher the message you will see an error message. Maybe you don not have the correct passsword.
You have more options at Settings. There is a Premium option to create several passwords, one for every friend or groups of Friends