The top of the window contains a menu bar with commands available.
File menu you can store the project or
open another project instead.
The upper left part of the ArgoUML window shows a tree model of diagrams and objects. This view can be adapted to your needs by filtering the objects that are shown, and the structure in which they are shown.
The upper right part of ArgoUML shows the current diagram (one at a time). You can drag and drop the objects in the diagrams, and you can use the quick-links that appear when hovering over a selected object to create new objects connected to the already present objects.
The lower right part contains various details of the currently selected object: You select the object in one of the upper levels and choose what details you want to examine using the tabs.
The lower left part contains a list of all ToDo items for this model.