Joomla ACL Actions Explained
The Joomla Access Control List feature allows site owners to place users into groups and those groups can be given permissions as to who can create and manage content. This post explains the different actions that groups can perform.

The Joomla ACL provides two main functions; it can restrict who can view certain content and who can take action on content items, for example create an article. This post explains the basic steps for the first part - how to restrict which users can view content.