How do I delay posting an Announcement until a specific date?
If you want to create announcements to post at a certain date and time, follow these steps.
Make Announcement Button
Click the Make an Announcement button.
Type a title for the Announcement in the title field  and add content in the Rich Content Editor . Click the Delay posting checkbox .
View More Options
Once you add the Announcement, it will show up on the Announcements page. However, since you delayed the posting, it will have the reminder that "This topic will not be visible to users until DATE at TIME."