Tools for different eDrawings panes are located at bottom right of the window to let you manage file information.
When you open a file, only the tools that are applicable to the specific file are shown. For example, when you open an assembly file, the
Components 
tool is available.
Certain functionality, such as the ability to mark up and measure files, is available only if you have eDrawings Professional installed. See
eDrawings Professional Overview for more information.