If you want to build a Jumper, just go to this link:

http://www.paperaviation.de/PuddleJumper/puddlejumper.html

There you can download a PDF document for free, it contains papercraft pieces for the jumper and an instruction how to build it. You need to print it very large so that it fits with the figures, though. If you have any questions feel free to drop me a private message, I am happy to help!