Highlight a confidant, choose message decryption
Highlight in your roster the person that you received the message from. Click Decrypt Message.
Type or paste a message
You are shown this page with an area into which you can paste an encrypted message. Again, under the heading there is a reminder of who your confidant is.
Let's copy into our clipboard (Ctrl-A, Ctrl-C) the encrypted Zimmermann telegram from the preceding help page. Then click in the text area here, and input Ctrl-V to paste in the entire message.
Don't worry about spaces and line ends. They are ignored. What matters is that all the printable characters are captured in order as they came out of the encryption process.
File version of the decrypted message
Click Decrypt This Message. You are shown:
The message is named again by its date and time. This time the word ".decrypted" is inserted within the name.
Extra display of the decrypted message
Click OK. You have the file and are good to go. But if there are no accented letters and if the length is reasonable, you see extra information -- the decrypted message.
Scroll down to see the latter part.
From here, you may either decrypt another message from the same confidant or to go back to the roster.