How do I set up the forums like the demo?
The forums seen in the demo site are created using the bbPress plugin. Please install and activate this plugin from Plugins > Add New and search for "bbpress".
Once you've activated the plugin your forums should be located at http://my-domain.com/forums for example.
To set up the forum layout seen in the theme demo you need to create category parents for each group of forums. For example on the demo forum (http://socialize.wpengine.com/forums/), "General" is a forum category and it has two child forums called "General Chat" and "Random Discussion".
Go to Forums > New Forum to create a header and on the right hand side select "Category" from the Type dropdown menu.
To create a forum under this header go to Forums > New Forum and on the right hand side select "Forum" from the Type dropdown menu.
This is how the final product looks.