Why you should use Child Theme
If you plan to edit theme files, then it would be good idea to use for this purpose child theme. This way, when you will update main theme, you will not lose your modifications.
Anyone interested in this should read http://codex.wordpress.org/Child_Themes for more information.
Be aware that using child theme is not bulletproof method. For example if main theme will change drastically in same part that you have edited via Child theme, then your site might not work proper. However this is rare situation, but is good habit to review your child theme changes after main theme update.
About theme modifications you can read in Modifications section.
Install Child Theme
First you need to get child theme file that you can install. It is ZIP archive.
In file downloaded form ThemeForest there is attached sample child theme. It is located in Child Theme\themename_child.zip in “All files” package
To install it please follow these steps:
- Install normal theme.
- Repeat step 1 but now install child theme.
- Activate child theme.
Now you can overwrite styles, theme functions and even whole templates. We explore it in Modifications section.