To be able to access the SiteAdmin features you must have the advances user access permisison of SiteAdmin for your own account. In addition you will need this advance access level for each site individually.
Main toolbar
A SiteAdmin menu is visible on the Main Toolbar to those users with SiteAdmin access and when clicked will shows the SiteAdmin sections and features of the system.
From the site selection menu of the main toolbar select the site you wish to carry out SiteAdmin actions in.
Click on SiteAdmin menu option of the main toolbar
Dashboard
There are buttons on the Dashboard for SiteAdmin users which enable them to access the manage user and cases features.