If you are working with the theme files manually, here is a general workflow for adding features to :

(e.g., modifying the AJAX cart behavior, changing how product variants are displayed, or adding a custom filter).

While I can't directly open or "develop" that specific local .rar file for you, I can certainly help you build the feature if you describe what you need it to do. is one of the most popular multipurpose themes on ThemeForest .