How can I add a Content Management System to my website?

I have build a blog website using HTML and CSS, the way the website works is that the header of the blog post is visible, and when you click on it, it should go that blog post. But it seems odd creating an HTML page for every blog, and I know you can use a CMS but I couldn't find any YouTube video on how to add a CMS to my website and handed to my client.