Hi Shrini,
Floor Plan Manager is a framework that can be used to create new WD Applications and configure existing regular applications so as to give them a standardized design. You can reuse existing components and use them in one single application by performing FPM configuration saving much time. FPM has predefined templates for rendering data in say tabular format or as a form. To understand how FPM works you will need to start by creating an FPM application...you can use - Floor Plan Manager for Newbies (Part 1) Simple Web Dynpro ABAP Application using Object Instance Floor Plan
and read some here....
Floorplan Manager for Web Dynpro ABAP - SAP NetWeaver by Key Capability - SAP Library
Thanks
Vipin