For thouse like me who are not firm with composer, the goal is that composer create a "vendor" subfolder, in this subfolder are all files about the installed script. In my case all controllers and modells about the shield-extension.

The connection from the main-folder and the main-framework scripts in the "app" folder will create on setup command (in my case "php spark shield:setup") here all the things will done (create tables in database, extend the base_controller and modells with the controllers in the vendort-subfolder etc.