Step 8: Glue!
Picture 2 - Mask off the lens it self
Picture 3 - Glue around the edge of the lens, and use the excess to hold it in place underneath
Picture 4 - Sand off the excess ontop.
The lens ive used here is again off the repromaster - For this section i printed off a picture of the sun, and taped it to the underneath.
Also for this bit you can use anything, a hunk of metal, a pebble, what ever you think looks cool.