Building Custom Themes
There are three main ways to develop a custom theme. The first way is to build a theme from scratch, writing all of the necessary files and creating all of the assets. This has the advantage of being entirely original, and ensures the ownership of the theme. However, this is also the most labor intensive way to develop a theme. A second method is to just select an already developed theme (also known as a framework) and simply customize it however you want. This is the quickest way to an end result. It does require that you pay attention to ownership of the theme. It is also necessary to choose a theme that is close to the end result you want, or else customizing it may be labor intensive. A third option is to begin with a starter theme. This a base theme that allows you to generate a new theme of your own without having to build it all from scratch. This is probably the method I would choose.
There are several types of files that are used to build a theme. One required file is called “index.php”. This file is the default starting file WordPress uses to display content as web pages. The content in this file is usually broken out into separate files such as “content.php”, “header.php”, “footer.php”, and “sidebar.php”. These files process the content that appears in the main body, header, footer, or sidebar of the theme, respectively. Finally, another necessary file is the “style.css” file. This file contains some necessary basic theme metadata as a comment at the top of the file, as well as some basic css styling.