Once 2sxc has been installed as a DNN extension, the portal must be configured. It's allows each portal could have different designs and apps as you need. 

Typically you'll do this right after installing 2sxc in DNN, on whenever you add more portals to your installation. 

1. if you have a multi-language site, you should first configure the languages - why
2. install a content-templates package, which determines the layout of content
3. install the standard apps or any app you want.