The Graphic Organizer in the Writer tool is synchronized with the Notecard function. It enables you to organize note cards into different sequences -- you can move topics around and reorganize them to test out different structures for your writing projects. As you move notecards around in the organizer, you can see a "graphical" relationship between them, so you can think about how the subjects in each notecard are related, and how you want to stucture them in your Writer project.
For example, imagine that you have created four notecards to start outlining the structure of your writing project, and that you have saved these notecards to your project, so that you can see them on their dedicated page.
Next, click the Graphic Organizer icon at the top of the Writer window. In the Graphic Organizer section, you will see your notecards represented as boxes that are connected, and that you can move around the page.
By moving your notecards into different orders, you can try structuring your composition in different ways. You can also always delete note cards and create new ones--you can do this from either the Notecard tool or the Graphic Organizer tool.