In broad terms, what are the essential elements of your invention?
Provide a description of each element of the embodiment (version) of the invention described in the broadest (least limited) claim. The idea here is to give the inventor a chance to pare down a description to the bare minimum elements of the simplest form of the invention. The goal is to end up with a listing of invention elements that illustrates how the elements are related to one another and that contains no words that unnecessarily narrow the breadth of the invention.
Hint! Think like a competitor who wants to gain the benefits of your invention without paying your organization a royalty. What element(s) could he leave out and still have a fully functional invention? You should leave them out of this listing, too. Can you think of broader (less limiting) language with which to describe any element? If so, use it. This is one of two places in an invention disclosure (the other is in the claims) where less (words) is more.
The objective of this effort is to "distill" the "essence" of your invention. In later sections of the disclosure, you will be asked to add all the bells and whistles that make your invention even better than its absolutely required essence.