If you want to add your own customizations to a readymade WordPress theme downloaded from here or elsewhere, the most obvious way to do it is to directly edit the template files and style.css of the theme. But this method can lead to complications when the theme author updates the theme to a newer version. If you directly overwrite the files from the newer version, you will lose all your customizations. So, you will have to check every file of the new version for changes, and apply those changes to your customized files. This can be a demanding process especially if you are using a theme that’s updated frequently. Alternatively you may choose to skip the upgrade process, in which case you may miss out on important security updates.
This is where theme inheritance is such a versatile method to add your own customizations to a theme. Creating a child theme is as simple as creating a folder and putting a style.css file into it with a just a few lines of code. With theme inheritance, you don’t have to miss out on updates to the parent theme, and your customizations will never be overwritten.
For example, if you want to customize the F2 theme, here is how to do it. Continue reading Using theme inheritance to customize your theme