Here's my sample menorah:
For the backs, I cut out a bunch of fin shapes from a few cereal boxes I had saved up. As the event I had the kids/parents let me know when they were finished crafting, so I could glue a kick-stand on the back. I could have glued them on before the event, but I didn't want anyone to accidentally craft their menorah upside-down. This way, it didn't matter which end was up until I added the stand.