Draw the outline of a 5-pointed star on the middle line of the tray, either freehand or using a cut-out cardboard shape.
Fold the star in half 5 times, along the bisector of each point, using the ruler to help you.
Shape the star using the folded lines to obtain a 3D effect, then spray it with the water-based spray paint.
Make a hole with the hole puncher and thread a piece of ribbon through it, so that you can tie the star to a napkin to decorate the table at Christmas. Attach a cardboard tag as an extra decoration or to use as a place card.