The Adobe Digital Enterprise Platform consists of two technology stacks – the Experience Server and the Document Server. The combined architecture provides services required for various Customer Experience Solutions.
The Experience Server needs to be integrated (configured) with the Document Services to leverage services that address multiple enterprise applications requirements around content creation, management, protection, distribution and enterprise workflows. The below video not only shows the steps to configure your Document Server instance with your Experience server, but also talks about building web applications that use Document Services.
You may also check out the published documentation on the exact steps to be performed.