You step back and look at what is a need and what is a want. You need to show your research through your product. You know that you don't know what that research really is yet, because you haven't defined it. You want the product to be really cool, and you want to demonstrate your killer making skills.
This amount of freedom can be overwhelming and debilitating for some students especially if they have only ever been exposed to more traditional research assignments where many of the decisions are made for them. Scaffolding by taking the group through activities that help identify research questions, look at different ways of communicating a message, and developing clarity around the telling of the research's story will help to eliviate some of this stress and keep students moving forward. Individual time with students to support their specific needs should be built in to the process around this point as well.