[Zope] Searching the Catalog

Hello, .. new day, new questions :-) A have a ZCatalog where instances of my zclass are cataloged. I added a search interface, and got three different input fields for searching three different attributes of the zclass. Now my question: I want to have only one input field, for searching all the three attributes. What syntax do I need? I have no idea where to place this syntax - in the searchform or reportform? Hopefully someone understands my question ... Marc