There are a number of reasons that WordPress developers are starting to use child themes. They give you the opportunity to customize a unique layout on top of another existing theme. This is perfect for beginners who want to play around with building their own themes.
Additionally many premium designs will release new updates over time. If you are making changes to core theme files they will be overwritten when performing an update, but child themes are separate and neatly tucked away. This means you can build off existing premium themes and save loads of time in the process.
In this guide I want to introduce the basic concepts of building a WordPress child theme
This article is about developing WordPress Themes. If you wish to learn more about how to install and use Themes, review Using Themes. This topic differs from Using Themes because it discusses the technical aspects of writing code to build your own Themes rather than how to activate Themes or where to obtain new Themes.
WordPress Themes are files that work together to create the design and functionality of a WordPress site. Each Theme may be different, offering many choices for site owners to instantly change their website look.
A WordPress Theme is a collection of files that work together to produce a graphical interface with an underlying, unifying design for a blog. WordPress.com currently has a very diverse collection of over 210 gorgeous themes (and we’re always adding more!), which you can browse in the Theme Showcase.
To activate a theme, visit Appearance -> Themes in any blog’s dashboard. You can change your theme as often as you like.