To make the top, cut the foam core to size so it will fit on top of the entire unit. Cut batting to the size of the foam core, then cut the fabric, allowing enough extra on each side to wrap the foam core and the batting like a package. Lay fabric face down, and place batting on it. Place the foam core on the batting. Wrap the fabric around the batting and foam like a package, and hold it in place using pins.
Cover ends with masking tape if desired.