Here's what I did:
I made the Jello according to the "mold" instructions.
Since the plastic eggs have two holes in them, I covered those with hot glue. You will also want to pull apart the eggs completely (don't have then connected at the side - that's how mine came) I then dipped the eggs under the jello and fill them all the way. While they are still submerged, snap them shut.
Rinse them under water to clean them off then store in an egg carton upside down. You do it upside down so that if there are air bubbles, they will be at the bottom of the egg rather than the top.
Warning: Your hands will get stained!
Leave the Jello in the fridge for a few hours. When it is done setting, take the eggs out and put them in warm/hot water for 30 seconds. This helps you get them out of the mold
I rinsed them under cold water and they were done. Like I said - not super pretty to take pictures of (maybe it's just the colors I did) but they are fun!