Import STEP and Mapping TopoDS

Hello,

I want to step data import into TopoDS data.

So, i read Data Exchange- STEP user manual, and i find StepToTopoDS_* class

But, i don't know that how can i using this class

In the manual, for using StepToTopoDS Class, i must call the Transfer_TransferProcess, STEPControl_ActorRead, and StepTopoDS_Builder(in the Graph of calls)

so i try like this,

/*----------------------------------*/
.
.
.
IFSelect_ReturnStatus status = aReader.ReadFile(aFileName);

if (status != IFSelect_RetDone)
{
return status;
}
//
//Some code for transfer ex) Standard_Boolean ok = aReader.TransferRoot(i);
//
Handle(TColStd_HSequenceOfTransient) list = aReader.GiveList();
Handle(STEPControl_ActorRead) actor = new STEPControl_ActorRead();
for (i = 1; i Handle(Standard_Transient) start = list->Value(i);
Standard_Boolean OK = actor->Recognize(start);
}
//Call STEPControl_ActorRead Class
//Call StepToTopoDS_Builder
//Call StepToTopoDS_Translate* Class
.
.
.
/*----------------------------------*/
I know, this is not good code...
So, how can using the StepToTopoDS_* Class?
Please, show me some example code or process for call this classes.

Thank you, Have a nice day!