Hi Pat. The rails are screwed into the settees, so all we have to do is
1. lay down the slats,
2. slide the super-thin plywood out from under the settee cushion to cover the slats, and
3. lay down the cushions.
The cushions in the photo are our cockpit cushions, and they fill the rectangle perfectly.
The slats are made of 4x1 white oak. The ends of the slats rest on the rails, and they are flush with the top of the settees, so when we lay the cushions, they are even with the settee cushions.
It takes about 45 seconds to assemble, and all the materials are lightweight! Throw on sheets, a blanket, and some pillows, and you are in business. It is ver comfortable, and very roomy! We are thrilled with it. We mounted the stereo right next to it, and I am going to move our light dimmer switch next to it too, so we can reach them from bed.
Let me know if you want more detailed photos.
-Andrew