working with SWMM software part 1

SWMM is a software produced by EPA (Environmental Protection Agency) of U.S.A . It is a free software used for developing the required data for drainage design. After showing the proper ground surface , catchment area and pipeline, the software generates the discharge at the various points. The full form of SWMM is Stormwater Management model.
So , right now , i am basically trying to learn the software and run it for the project as well. another alternative to this software could be Autodest Stormwater and sanitary analysis software.
 the project that i am doing is an urban development project where i have to design the storm water drain system . i need to determine the discharge at different nodes of the system. to determine that i want to import a jpeg image which i have taken out from an autocad drawing. I want to insert the jpeg image in to swmm and determine the pipe system in swmm according to that.