The content is a separate section below the Revit application itself. It is important to review the settings lurking within the Content section too.
Assuming that was done then we should find the content installed in the default location or where we decided to put the content ourselves. This is the default location with individual sub-folders within it for each unique library you've selected:
C:\ProgramData\Autodesk\RVT 2016\Libraries\US Imperial or US Metric etc
Still no content in this location, or the one you chose instead?
Revit downloads the content libraries you've selected to install so perhaps this task is being blocked by anti-virus, user permissions or internet access/restrictions? That's quite a conundrum for many people.
Making it a little more difficult, when you visit a related help document at Autodesk's Knowledge Network it describes the situation for 2015 and tells us to use the Control Panel Add/Remove feature. Fair enough for 2015 but for 2016 I find no such option for Content, despite the article specifically claiming it is similar for 2016. In fact I don't find such an option for 2015 either on my computer. FWIW, I only see an entry for Autodesk Content Service.
RAND IMAGINiT has made some of the content available via a blog post of theirs. It might help to try downloading it from their FTP site.
Autodesk Seek also hosts Revit content including its own library. If you visit the site, at the bottom of the page they have links for each disciplines library.
While I can download specific families and templates from that location I don't see an easy way to just download the entire library. They used to provide a page where we could just browse for and download a library bundle, for any of the localised versions too. I've not found its equal yet.