In the main page of the Theme Configuration, the Configuration tab is where you configure general RefinedTheme for Confluence settings and activate the global Confluence theme.
Access it through the admin section of Confluence under the RefinedTheme Configuration, or directly from the settings cog.
What's what in the Configuration page?
Settings that are applied in the Theme Configuration are applied globally, meaning that they will apply to any site or any category in your Confluence.
To learn more about a setting, hover it and click the information icon on each setting.