You should have received four slat support boards in your futon shipment. The assembly hardware pack you received was missing four of the 30mm bolts to add the slat supports to the slats.
To add the slat supports to your already assembled frame, please see the diagram and use the steps below.
Remove the futon mattress.
Please locate the two slats with the two extra holes in them either on the seat deck or the back deck. Using the bolts provided, screw in the slat supports underneath the slat. These supports add another layer of strength to your frame so please add them. We apologize for this inconvenience.
If you have any questions, please contact us at 763-786-3784 or support@stratafurniture.com