Hello! Yes, the stools are secured using the slot in the seat, and the side chair cushions are attached through screws going through the holes in the seat.

Hi. I received my stools, and they fit in the slots, but did not come with any screws or hardware to keep them in place as described above? So they don't stay in place unless someone is actually sitting in stool. How can I get the missing screws and place to hold them in place?

Sorry meant plate to hold in place.