Go to the package editor, click on the new button and select a new trigger

In the trigger dialog for pattern, enter the text you want to fire your echo off of. And in the script box, enter what you want to have your client do

For instance
Pattern:You are hungry.
Script: #ECHO ====EAT YOU FOOL===

From the command line you can also create a trigger

#TRIGGER {You are hungry} {#ECHO ====EAT YOU FOOL===}

CMUD documentation is pretty solid so you should be able to get anything you need from there the help for editing triggers in the package editor [forums.zuggsoft.com]