Hi
""OB03 means moving goods from workcenter to staging area(9025).
But when I see the storage type configuration I could see that in external step OB03 is maintained. What is the relevance here?""
As per SAP details
External Step
The External Step assigned to the storage type is only used if the HU moved into
the storage type has not yet achieved the assigned step within the routing profile
from the process-oriented storage control (POSC). In that case, the step assigned
to the storage type would replace the last completed external step assigned to the
HU. In the case of storage types for work centers, the process step assigned to the
work center is compared instead of the one assigned at the storage type level.
I hope it will help to see details.
now about rule base in OB03 it means door bin as rule based.
So you need to configure outbound door and there sequence in easy excess door determination in outbound which will act as rule based setting.
Regards
Suraj