Workspace
The top bar lets use control the size of the application window, or exit the application.
The line of action words provide access to most functions. The menu items are contextually activated, and other options are dimmed if unavailable.
The bar of icon button let you access the frequently used actions. The icons are contextually activated so only relevant icons can be accessed. Other icons are greyed if unavailable.
The left-hand pane shows a dynamic tree representing the hierarchy of entities maintained in your current model. The entries in the tree are easily searchable and let you directly access their properties.
The central pane is where you realize most of your work. Here, you visualize your data model ERD and entity hierarchical schema view.
The right-hand pane displays the properties for any entity you select in the Object browser or central pane. This is where you maintain the characteristics and constraints of each entity.
The relative width of the 3 panes can be adjusted by sliding sideways the vertical ellipse sign 
that can be found on each side of the central pane. When the you hover your mouse over the ellipse, the cursor changes to a two-sided arrow: 
. Click on the ellipse and hold your left mouse button, then drag right or left until the panes have the width you desire, then release your left mouse button.