[Zope] CatalogQuery newbie question

[Stephan Goeldi]

This must be a newbie question:

I installed ZCatalogQuery to search a Catalog for a certain word in
title OR PrincipiaSearchSource. The syntax is told to be:

Catalog(title=3D=E2=80=99spam=E2=80=99, PrincipiaSearchSource=3D=E2=80=99sp=
am=E2=80=99)

I don't know how the word 'spam' in this case is replaced by the text,
entered in a search form.

Can anybody provide me a working example of such a query in DTML?