Kibana, the visualization component of the ELK Stack, is used to create dashboards that display various metrics, such as page visits, server performance, and SEO data, through an extendable plugin infrastructure. A tutorial by Gilly Barr demonstrates how to add a traffic light visualization to Kibana, designed to show metrics as green, yellow, or red to indicate good, average, and bad status, respectively. The tutorial guides users through the process of creating a new directory for the visualization, registering it in Kibana's registry of visualization types, and defining its properties using HTML, CSS, and JavaScript. The traffic light visualization utilizes Kibana's TemplateVisType object for rendering, allowing users to customize parameters like width and threshold values through an intuitive editor interface. The controller component manages data from Elasticsearch queries and formats it for the visualization, providing a clear example of how to extend Kibana's functionality for specific visualization needs.