The main body of the Kirrkirr window displays the content of the dictionary in a variety of ways, or lets you look for content, or play games based on that content.
There are 7 tabbed panes that you can choose between to do different things. Click on a particular tab to see what it provides, or read the help about it by clicking on the tab name on the left.
The main body of the window is divided into two by a divider. You can move this divider up or down (but not beyond a minimum size for each half of the window). By clicking on the little triangles at the left end of the divider bar, you can choose to display just one half or the other. This allows you to have a bigger view of one kind of content.