The Query tab allows the entry of query parameters as defined during creation and setup. If the report has been set up to enter query parameters, you may enter query information, which will give report results based on records that match the parameters you entered, or you can run a report on all records by leaving the field blank.
User-Defined Report (UDR) and Query-Based Tab
Users will be able to use the Summary Elements, from any of the QBTs, in any of the UDRs that the user wants to use if the UDR is based on the same business process record.