How Do I Build A Helicase Model & What Are Its Functional Groups?

Hi, my name is Brittany.  I am going to be in AP Biology this upcoming year so I have summer work.  A part of what I have to do is build a helicase model.  I looked up pictures of Helicase and It looked to be 6 little circles that were all together.  I just wanted to make sure that this was a correct picture and that I could make it out of puff balls or something similar to represent them.

As far as the functional groups I am totally confused.  I know there are common groups but I am not able to tell when it is a functional group and when its not. 

Thank you so much  and hope someone can reply soon!!!