A tutorial provides a step-by-step guide on how to replace the default WYSIWYG editor in Strapi's Content Manager with CKEditor by creating a new plugin. The process begins with setting up a Strapi project and generating a plugin named "wysiwyg." The tutorial details the creation of three components—MediaLib, Editor, and Wysiwyg—to seamlessly integrate CKEditor, allowing for enhanced media handling and text editing. The MediaLib component manages media insertion, while the Editor utilizes CKEditor to offer a comprehensive editing experience. The Wysiwyg component wraps CKEditor, providing a user-friendly interface and integrating media library functionality. Finally, the new WYSIWYG field is registered using the addFields() method, enabling CKEditor to replace the default editor in new content types.