Creating Child Themes
Installed (Parent) themes should never be changed because after theme update your changes will be lost. Instead use child theme which is an extension of the parent theme and will not get overwritten when parent theme gets updated.
This type of work is mainly for developers or someone who has some basic knowledge of PHP and CSS. Please see the following pages for detail information on how to create and update your child theme:
Always remember to backup your website or make changes on staging / test site before changing files.