A CMS, or Content Management System, is a web application that allows users to create, manage, and update the content of a website. In this article, we will discuss how to build a CMS using PHP, one of the most popular programming languages for web development.

1. Setup:
Start by setting up a local development environment. Install a web server (e.g., Apache), PHP, and a database server (e.g., MySQL).

2. Create a database:
Create a new database using a database management tool (e.g., phpMyAdmin). Set up tables to store website content such as pages, posts, categories, etc.

3. Create the basic structure:
Create a folder structure for your CMS project. At minimum, you’ll need a main index.php file that acts as the entry point for the application. All other pages will be included based on the user’s request.

4. Create a router:
Implement a router that handles incoming requests and directs them to the appropriate controller. This can be done by parsing the URL and mapping it to a specific controller and action.

5. Implement authentication:
Add a user authentication system to your CMS. This will enable users to log in and perform actions such as creating, editing, and deleting content. Store user credentials securely and handle authentication checks in the router.

6. Create controllers and models:
Create controllers and models to handle different functionalities of your CMS, such as creating, editing, and deleting content. A controller handles the logic of user interactions, while a model interacts with the database.

7. Implement CRUD operations:
Implement CRUD (Create, Read, Update, Delete) operations for managing content. For example, create a page that allows users to create a new post, view existing posts, edit posts, and delete posts. Use SQL queries to interact with the database.

8. Add a WYSIWYG editor:
Integrate a WYSIWYG (What You See Is What You Get) editor like CKEditor or TinyMCE to provide a user-friendly content creation experience. This allows users to format their content without writing HTML code.

9. Implement front-end templates:
Create front-end templates for the website’s pages using HTML, CSS, and JavaScript. Use PHP templating techniques (e.g., using include files, placeholders, etc.) to dynamically populate content from the database.

10. Implement additional features:
Depending on your requirements, you can add additional features to your CMS, such as user roles and permission management, media management, SEO optimization, caching, etc.

11. Test and debug:
Test your CMS thoroughly to ensure all functionalities are working as expected. Identify and fix any bugs or issues that arise during testing.

12. Deploy:
Once you are satisfied with your CMS, deploy it to a production server and configure the necessary settings (e.g., domain name, DNS, SSL certificates, etc.).

Building a CMS with PHP requires a good understanding of web development principles and PHP programming. Additionally, it is recommended to follow best practices for security, performance, and scalability.