Tell us about yourself!
It's getting the exposed wire taped to the battery terminals. Once you tape the wire it tends to separate under the tape and is tricky to successfully tape the wire strands against the terminals. Also, don't use a curve like a heart, instead do a triangle or square because the rounded areas are to difficult to tape.
I plan on doing this at a library with after school kids. I used conductive adhesive copper tape instead of the metal and brads - much easier! The hardest part for kids will be wrapping the exposed wire around the battery terminals. I might prep this part for some of the younger kids.
Operation Valentine: A Game, a Gift, a Lesson in Electric Circuits