Usecase1 : Selecting record from table in left region reflects dependent detail form of same table in right region using InputParameters
Here is the example given by Andre Example
Three important crux to be known from above example.
1) create primary key attribute in pagedef of the table in region1
2) add inputparameter name in taskflow inputparameters of region2
3) bind primary key attribute from page definition to above inputparameters in main page where above 2 regions dropped.

UseCase2 : Selecting record from location table in left region reflects corresponding department records from department table in right regions.

1) create bind variable on location id in departmentVO.
2) create inputparameter say LocationParam, with type Number, value as #{pageFlowScope.LocationParam}
3) assign LocationId param from pagedef to LocationParam in taskflow2
4) create ExecuteWithParam action in region2 pagedef and invoke the same on IfRefresh condition.

during run time - steps executes in backwards (3,2,1)..i,e as user selects column in location table, it assigns location from pagedef to locationParam and then to PageFlowScope and from there to view criteria.