Edit sidebar, footer, copyright
Tutorials for WPKoi Themes
Customize widget areas and footer
Most sidebar and footer functions are in the customizer. You can add content with widgets.
Add content to Your sidebar and footer at Widgets menu in Your admin. There are panels for sidebars, footer and bottom bar. You can add text widgets, menus etc.
You can setup these areas in the customizer (Appearance-> Customize). The function are in the Layout section.
The premium versions have more functions like paddings, color and typography change etc.
You can change the copyright text with the premium versions also at the customizers Layout-> Footer section. With the free themes, You can hide it with some additional CSS code.