Child Theme

This theme includes a child theme to make the changes easier.

If you plan to add a lot of CSS changes or add your own customization of HTML or PHP, it is highly recommended to do these changes inside a Child Theme, so you will never lose these changes.

So just install the theme__name-child.zip like a wordpress theme. You can add your CSS in style.css inside the theme__name-child folder or overwrite theme templates inside it. Learn more about child theme here.