Step 1: What You Need

This is what you need if you are doing the bigger box...for my daughter I would be doing the cube...it's the same except there are no wheels. I would continue this instructable with the cube and post pictures of the bigger box later as i couldn't complete it.(my neighbor complained of the sanding noise so I'm waiting for the couple to leave on a nice long weekend!)

Step 2: Build the Box

Build a basic box...make sure it's square else it would not stack. Remember to first cut the slots for the finger hold. To cut the slots find the center point. Then mark 2 inches from the dot on either side. drill through on both ends...draw lines on the upper and lower curve and cut away with a jigsaw or band saw.
cut 2 square dowels the width of the finger hold planks...pass it through the box to make sure it would fit...then fix it at the bottom...you may glue,nail or do both!

Step 3: The Fun Part- Texturing and Painting

Prime/ gesso the boxes...giving it a textured background hides a lot of mistakes...plus children just love this part.
For more ideas on texturing check out the below instructable
https://www.instructables.com/id/Sculpturing-and-Texturing/

Paint and decorate how you like...I of course went for the rainbow colors.
Cut numbers in a mirror sticker and paste on one side...you can put on the other side pictures of what you want inside the box