What is a child theme?
A child theme is a theme that inherits the functionality from the parent theme and are often used when you want to make changes to the theme that goes beyond the default options. Changing code directly to the theme files from the parent theme is not possible because you will loose them when you update the theme, this is why installing a child theme will help you.
Where can i find the Cargoly Child Theme?
The Fittlife Child Theme is included inside the “All files & documentation” package from ThemeForest. If you want to use the child theme upload it through the WordPress dashboard (zip file) or ftp (unzipped folder). Please see Upload Theme how to upload and activate the child theme.
Install child theme before making changes to the parent theme
Install the child theme always before you’ve made any changes to the theme customizer under Appearance → Customize. If you already made a lot of changes there use the “Customizer Import/Export” plugin to export the customization on the parent theme and import that file when the child theme is activated.