Workspace Apps include 3 window panes; Navigation, Content and Properties. These panes may be both resized and hidden.
To resize a pane, simply drag the pane divider left or right. To hide a pane, simply click on the "x" in the upper right or left corner of the pane.
To display the left Navigation Pane, click the Restore Window icon in the upper left side of the window. To display the Properties Pane, click the Hamburger icon in the upper right side of the window.