Before you can write a query in QBE, you need to display the QBE Query panel. There are two ways to do this from the command line on the QMF Home panel. The method you choose depends on whether you plan to use QBE most of the time or switch back and forth between query languages.
SET PROFILE (LANGUAGE=QBE RESET QUERY SAVE PROFILE
RESET QUERY (LANGUAGE=QBE