File Structure

└───marketplace_builder
    └───views
        └───partials
            └───layouts
                └───categories
                    ├───detail
                    │       custom_example.liquid
                    │       default.liquid
                    │
                    └───list
                            breadcrumb.liquid
                            children.liquid
                            items.liquid
                            parent.liquid

If inside Siteglide Admin Code Editor, start at "layouts".

You can only have one Category Detail Layout active at a time. You can use logic and Content Sections to run different code depending on the Category.