Add the last bit, with the parent. SS should automatically associate that dataobject to the parent page, and will then be filtered automatically by the dataobject_manager module (or a complex_table field for that matter)

Hi glenn, thanks for the reply but 'Parent' => 'Page doesn't work. however i noticed that in http://doc.silverstripe.org/modules:dataobjectmanager it says "The primary difference between a FileDataObjectManager and a standard DataObjectManager is that its focus is on the File object related to the DataObject. By default, all the records in a FileDataObjectManager are displayed in a grid view, each represented by an icon of its related File object." but it displayed all files that are already uploaded when creating a new record.