To understand how template files work, see Template Files. WordPress searches for specific template filenames to display certain pages on your blog. If it does not find any filenames in the theme, it will resort to a more general template file, up to the index.php. If no other template files are found, it will only use index.php to display all pages of your site. Once you have chosen a theme, you can configure it to look exactly how you want it.
If you are not sure how to get started, follow the steps on this page. You can choose a free theme in the theme panel when you install WordPress. However, most WordPress users opt for a premium theme that offers a better design and more customization features than free ones. If you want to make edits to your theme template files, you need to figure out which template file is being used to display the page you're viewing. For example, every time you upload a new blog post image, it is stored as a JPG or PNG file in the theme folder. A child theme of WordPress adds an extra layer of extensibility and security to a website and theme because you don't need to write a lot of code or modify the parent theme files at all.
It is also not a bad idea for anyone who uses a WordPress theme to know at least the basics. Downloading and installing themes is easy when done directly on WordPress. When you start with WordPress, it can be difficult to find the right information about how to do simple things such as adding a thumbnail to a publication or creating a menu. The parent theme lays the foundation for that website and is often not as customized as the child theme. The right theme can display your blog posts in one way while offering a completely different layout for your store pages. If you have a specific vision for your site, you can choose an appropriate theme and customize it to meet your requirements. WordPress alone offers a complete content management system for adding pages, menus, media elements, blog posts, and more. Finally, all these queries that WordPress does to build each page is why caching really helps speed up your site.
It is also important to know that specific files are required for every WordPress theme.