I think you should check the local laws first. Sure you can bolt an eBay engine kit straight on but it might not be road legal depending on your location. Also browse the forum and read the newbie threads, and read read read. It's free and people put a lot of time into posting about their knowledge and experience of this hobby so it would be a great waste to not spend at least a week of evenings reading about the possibilities and pitfalls. And remember that Peugeot bicycles weren't intended for motored use so wear a helmet.