I didn't have Shimmer in my main world so I made a new small world just for this. I found a Living Tree above The Aether and pumped the Shimmer up to make a lake with an actuated trapdoor by a little treehouse.
Place your Fallen Star Sticker on this STAR CANNON Crafting Station to craft Star Cannon stickers!
As you craft weapons, they'll appear in your list of stickers! When you see the weapon fill in on the post, it's exhausted and you can't craft any more.