http://www.jshs.org/guidelines.html
I think that you can find everything you need by poking around on this link.
To compete, you need to write a full paper and then make a presentation in front of judges. The time limit (12 minutes) is strictly enforced.
In my opinion, the judging is very subjective. They seemed to favor research topics in their own areas and generally asked very banal questions for presentations in areas that they weren’t familiar with. It appeared that the judges did not read the papers before the session. We got a fantastic breakfast before the competition though 