In order to activate Plesk Sitebuilder you need to go under Settings -> Modules -> Hosting Modules. Then, you have to click 'Activate' tab next to Plesk Sitebuilder module. To configure the activated module, you ought to go under Settings -> Apps -> Add New App. Once, Plesk Sitebuilder is added as a new app you can start its configuration.
Manage space
Manage content
Integrations