Oracle Reports/Layout "Null Collapse"

I'm just learning Oracle Reports (for last 2 months) ... I'm trying to use and make notes on how to have something like an address field collapse ... I use anchors, make them collapse vertically ... then inside of the "boilerplate" text box ... I think "edit" section ... I put "code" to say if this is NULL then ... "Return False" ... What would be the easier way to explain (for me to understand later) ... how to decide what should be NULL for it to return FALSE ... meaning, is it the "Field" option list I should go to ... and then what ... the Column Placeholder name (cp_name) ... or if it references the Main Query use simply ":name" ... How is my thinking on the subject? Any input at all or

advance tips would be appreciated.  Roy                    ProfWdesk1_at_aol.com