Navigation:  System Setup (F4) > User Groups > Sites Tab

Select Site(s) the user group should have access to.  Note, for Site Users that will be seeing the Web Portal Dashboard, select their site under the Sites tab, otherwise, they will see data for all sites on the dashboard.  For internal typists of an MTSO, this is usually left blank, as you can control what jobs they get through work pools.  If they have access to document search, you can restrict what sites they have access to bu using this setting.