When you purchase an upgrade to Journalist PRO, you will receive an email with a new Licence Key.
Once you have entered the new key in the "Registration Key" window (Mac menu: Hindenburg / Registration Key, Windows menu: Tools / Registration Key), restart Hindenburg and the PRO features will be enabled.
You will also see "Hindenburg Journalist PRO" in the title bar at the top of the program.
Hindenburg Support Team
Facebook: Hindenburg News