Stepmania Online

So yeah, just new to stepmania and dancepad games :3

a) Is there a "retry" button? I mean if I played a song I might just want to replay it to get a better score instead of going back to menu and selecting it again..

b) I saw a video of a DDE(R?) machine, the characters there actually were shown on a virtual dancepad... seems handy to me, especially since sometimes I don't know whats a good way to step to not end up in a bad spot haha... however somehow in Stepmania the characters just seem on the screen and oddly dancing about?

c) Whats a good way to learn? Just keep doing songs on easy/novice to get a better feeling of things I suppose?

The site is that most people dream about.

This is not osu! and most of these questions are related to the actual StepMania program, not the online functionallity.
If you want some real answers to these questions then go to the stepmania official forums.