Stacks are added to an extension’s structure in a /stack directory that is at the same level as the extension’s ext.json file. Each stack should have its own child directory in the /stack directory. The following example shows the directories and files that can be included for a stack:

<extension-name> : the root folder of your extension
    ext.json
    stack/
        <stack-type>/
            stack.json
            templates/
                stack.template
            less
                stack.less
                stack-variables.less
            locales/
                <locale code>.json
                <another locale code>.json