You can choose what selection fields you want to work with in the Selection Fields column of the upper left-hand window on your screen in the Query Painter.
Select those fields that you want displayed as selection criteria on your selection screen by placing a check in their checkbox. Selection fields are displayed as input fields on selection screens before your report is executed. Users can reduce the amount of data output in the report by entering values in these fields. If, for example, you select Flight Connection Code, you can specify in the program selection area that you only want to display flights with certain flight numbers.
Those selection fields mandated by your logical database or InfoSet are already selected.