In CSS Sculptor you are not able to reenter the wizard to make changes. Once the page is created, you will need to make your modification to the css that is being applied to the page. And Sculptor gives you the ability to save preset so any changes you make are saved in a custom preset that you could use more than once.
I would recommend you take a look at some documentation located at:
In regard to changing the margin or the color, that could be done easily by changing the css that is generated.
Let me know if you have any additional questions.