GNATbench defines a perspective dedicated to the Ada language. The icon representing this perspective (see the figure below) has the letter 'A' in the upper right, with standard Eclipse symbols denoting packages, types, and tasks in the center.
You can select this perspective by clicking on the Ada perspective icon at the upper right of the Eclipse window if the perspective is already opened. In the figure below, the Ada perspective icon is shown immediately to the right of the Workbench "open perspective" icon:
If it is not open already, you can activate the Ada perspective by clicking on the "open perspective" icon and choosing "Other..." and then Ada from the dialog box listing the perspectives. Alternatively, you can use the menu "Window-> Open Perspective-> Other..." to open that dialog box. The dialog box appears as follows:
