1. Have the incoming message open in your normal e-mail/news program.
2. Left-click the Mollusc 5 icon in the tool tray.
3. The PGP Enter Passphrase dialog may activate. Enter the required passphrase and click Ok
4. The Decryption/Verification Results dialog will show. You can opt to view the message.
How to save a received message as a disk file
How to print a received message
Why so few options for inward messages?
More advanced topic: Prefer key import over message reading