The Jetpack Instructions appear on PoptropiCon Island, Episode 1. There is an NPC waiting at the front of the line for the restrooms who has a broken Jetpack. When you talk to her, she will give you the instructions to build a new Jetpack, which she will trade her spot in line for. The player uses the instructions at Ye Olde Forgery of Finery to assemble the Jetpack out of the Bottles, Backpack Straps and Watch Parts.