Assembly
First re-crease the folds on the front piece. Then glue the rays to the blue background.
The tabs on the second and third piece fit into the slits cut into the front piece. Insert those before attaching the back of piece. The front piece then folds around the back of the blue piece and is glued via the ends of the front.
Next, the tabs from the middle pieces are folded over and glued down. You will need to trim them a little. I made them extra long to make it easier to fit them through the slots. After they are glued down attach the side pieces to cover the tabs.
Your Reson for the Season Nativity Shadowbox card is done! It does not fold flat so it is difficult to fit in an envelope but you are shipping boxes anyway this time of year.