If you are unsure if you scheduled your posts for the right time, you can check on your Manage Inventory page.  Go to your Manage Inventory page, and find your items on the table.  If they are scheduled to post to a Facebook group, they will list the name of the group, then say Facebook Queued.  Hover over this queued notification, and a box will pop up with the details of your queued post, including the date and time.