As I said, glue won't hold all that well (plus the wheels need to attach to something), so here we screwed on some boards to be the cross supports.
Screwing on the Cross Supports
With that support in place, we cut it with a circular saw against a straightedge to even it off (but I forgot to take the picture).
Ready to be cut even
I then screwed on the handles (hard to see, since they're matte black).
With the Handles - top
With the Handles - bottom