Check the condition(s) you want to make active (just check the check box on its left)
To each condition you have checked, fill the corresponding edit box right below, with the words you want to apply to applied to the checked condition. E.g. "with specific words in the subject" as the condition, and the word SUBSCRIBE in the edit box. If your action were "Subscribe Sender", the WorldCast would automatically subscribe all users which sent a message in which the subject contained the word SUBSCRIBE.