Post here if you have questions about creating SuperFlexi Solutions.
The SuperFlexi documentation is very thorough, so you might want to start there.
Within the demo site, you have a Parallex Effect (at the newsletter sign up section).... how did you do this? is it available in SuperFlexi?
If you are using the Scout skin, you can get that effect on your newsletter module by adding the "newsletter-cta" class to the Custom CSS Class option on your Newsletter Signup module instance. If you want to use it on another module, add the same class to its Custom CSS Class option. If you want to change the background image, you will need to duplicate the newsletter-cta CSS in the skin and change newsletter to something else in your duplicate. Then, you can change the image in the CSS of your duplicate. Finally, you would use duplicate-cta for the Custom CSS Class wherever you want to use it (of course, swap out duplicate with whatever you named it).
If you're not using the Scout skin. You can try copying the CSS for the newsletter-cta class from the scout skin to your skin. This may work but you will probably have to tweak some things to get it to work with your skin.