"Stoop" style porches

[37#gnome]

I am using Landscaping and Deck Designer 7.5 and I live in an area where there are many homes with a concrete stoop for a front porch, most without a roof. When I try to create it, I end up with a floating 4" thick concrete slab. I am having a devil of a time trying to create the substructure. Help?

Thanks.
Lee Ann
Landscaping and Deck Design 7.5