There is a tutorial for ECART which builds the Blue Sky Music store, I found it very helpful.
I've also found it worthwhile to build a solid foundation in css/html and php prior to using these tools.
I think folks see the ease of use as a means to point and click to an end result. The nature of dynamic applications is in contrast to that theory as pre-planning site development is vital to any web presence.
The e-cart tutorials, presuming you purchased the super suite, show you how to build out a web store....