This is a great project, especially because it was present for my cousin Michelle. It wasn't as easy as it looks but we figured it out.
What you need for this is
We discovered that you have to use permanent markers for this. The regular kid markers rub off and they aren't as dark. Hot glue is the best for this, but regular glue works too, it just takes longer. Just draw your picture on the cardboard. Make it a big picture without a lot of details. My picture had lots of lines but when we got to the glue part they didn't show through. Use your glue to outline all the lines on your picture. Then, cover the dry glue with foil and press it down so the glue forms ridges. You may have to use more than one layer of foil. It is real easy to poke through it. You color inside the ridges with the sharpies. When you are done coloring, outline the ridges with black. It looks so neat. We used construction paper for the frame.
There is a really great tutorial here ↓ Theirs came super cool! http://www.housingaforest.com/tinfoil-and-sharpies/
I found it in my online newspaper Lian's Picks for Kid Summer Fun