Print the gift box on heavy cardstock. Cut out the gift box, and use a rotary cutter with a scoring blade to score the line between the front and back of the box and the curved edges of the ellipses so you can fold the ends in easily.
Score the line between the glue tab and the back of the gift box, and bend it toward the inside. Spread glue on the tab and glue it inside the box. Let dry.
Fold in the back flap on one end, and then the front flap. Add the gift or gift card, and fold the final flaps in.