Draw context and diagram $0$ DFDs that represent:

$1.$ An order system

Use Visible Analyst or another CASE tool to create the data flow diagrams. Run some of the analysis reports. A good CASE tool will do much more than act as a graphics processor for diagrams. It should provide much more information than the analyst has entered. Some useful reports are:

A$.$ A data flow diagram syntax verification report for all diagrams

B$.$ A level balancing report