how to Sum in a SAP Query


I have given up....Really need some advice....

I need a report example: Order Number, Order Type, Order Date, Customer number, Net Price, Total order cost

I can get all I need from file VBAK, EXCEPT total order cost, which is at the line level (VBAP). Now I need to show one line per order and sum the cost field (VBAP/WAVWR)...

How can I accomplish this in SAP Query? IS this even possible?