Slobodan,
I’m trying Spark as well, how do you share the work you make on Spark?
What template do you use for these scrollable stories?
Once you are done with creating/editing a story, there will be this "Share" link:
As for templates, there is about a dozen to choose from, or create your own. You do not have to commit to one in the beginning. You can create the story and then work through templates to see which one is the most suitable. Even if you use canned templates, certain elements are customizable.
For 2018, I used my own color palette (ahmmm, lack of color - gray) and I tweaked their font selection a bit.