I thought it would be fair to make one more box and show you in pictures how to make it with me. It took me about three hours in total and that doesn't include the little hand-stitching around the border at the top (visible on the blue lining on the bottom box).
1. two pieces of fabric size: 45 cm x 13 cm
2. heavy fusible interfacing
3. embroidery thread (optional)
I will show you how to create a basic box, without any appliqué designs, nor embroidery. You could choose to decorate it as you wish. Make sure you work the design on the fabric that is for the face, prior to assemble the box.
Size: L x W x H : 8 cm x 8 cm x 6.5 cm
Here is how to make the fabric boxes.