Hello Raj,
I think your are developing the app from scratch using SAP back-end using SMP 3.0 Agentry framework. But it's very difficult to develop all the thinks like Work Manager, Inventory Manager, etc....I think SAP include Agentry in SMP for standard apps not for new development, If you want any new development for your business scenario you choose OData framework not Agentry framework. If your business scenario same like Inventory Manager or Work Manager, etc,, yous just take standard application and customize whatever you want that is the best way for exploring Agentry application otherwise it's very difficult to learn/develop from the scratch.
Thanks,
Ranjith Lingala