This a theme developed by a third-party so I would recommend reaching out to them directly for support. That being said, I did go through their documentation and found a guide for exactly what you're looking for. These 'product stories' come from the theme using templated 'sections' within the theme files. The reason why you are seeing the one 'story' across all products is that by default, you are creating only one templated section and it's applying that across all your products.
That guide above is going to show you how to create a new 'section' template (product story) within your theme file and how to apply it to a product(s). So in short, you can have unique product stories you will just be required to create a new 'section' template for each product.
I hope this helps! If there is anything else I can help you with, please let me know.
@Dirk Thank you very much for your comment. I have successfully created a new template and section in the code. I have also put one of my products onto the new template. However, how do you then assign the product story to a new product template?
@Trulines87 When you are in your admin, go to a product you want to edit, and at the bottom right of the page you will see a section called "Theme Templates - Template Suffix". Change that template to the one you have just designed.
If there is anything else I can help you with, please let me know.