...
See Additional Information here on Setting up Course Site Groups.
Note - The Notifications drop-down will appear blank if "Students submit in groups" is set to No. Once you switch that menu option to Yes you'll see the Notification settings.
Restrict Access - This setting allows faculty to hide and make available content on a specific day/time and for a specified amount of time.
Note - Restrict Access is NOT the due date. Due date is set up in availability.