I removed both rear twin beds to repair the subfloor, then re-installed the twin beds but wound up with an extra board on both sides. I can't believe that I didn't take pictures before I disassembled them.
The left over boards are about 3' long with an angle cut on each end and 2 holes drilled on each end. But where do they go?
If you have rear twin beds please look under the mattress and see where the extra board might properly go.