Should have a link pointing to the article, right now it just mentions it should be looked at.
To configure file upload limits, consult the article 'Configuring File Upload Limits' in the documentation.
https://secure.phabricator.com/book/phabricator/article/configuring_file_upload_limits/
I'm can try and tackle this shortly, in the process of finishing my own install though.
You can use PhabricatorEnv::getDoclink(...) to get the link to a documentation article.
Some options classes like PhabricatorSecurityConfigOptions and PhabricatorCoreConfigOptions look like they have example uses.
I'll hand this back to you for the moment; if you don't get to it we can get someone else to pick it up. Thanks for the report!