How to install child theme

– Install wpestate theme – http://helpv4.wpestatetheme.org/article/theme-installation/
– Find in the theme pack downloaded from theme forest the wpestate-child.zip folder (download all files and documentation from theme forest and unzip)
– Go to Themes – Appearance – Upload the wpestate-child.zip folder and activate child theme.
– Save menus

Via FTP:

– Login on your domain via FTP MANAGER

– Go to wp-content/themes and copy wpestate-child folder as given in theme pack

– Go to wp-admin/appearance/themes and activate the child theme

You can start adding CSS modifications right away.

For more complex changes documentation, go to http://codex.wordpress.org/Child_Themes