Learning to use the following tools will allow you to place objects in a Scene window with ease.
To test out the object manipulation tools, make sure you create one of the available 3D primitives in Unity via GameObject | 3D Object (Cube is recommended).
Object manipulation is done via five tools available on the left side of the toolbar:
Hand tool (used for panning), Move tool, Rotation tool, Scale tool, and Rect tool can be accessed via the toolbar or by using the hotkeys Q, W, E, R, T respectively
To duplicate an object, you can use Ctrl+D or a combination of Ctrl+C and Ctrl+V to copy and paste
You can undo the last action via the Ctrl+Z combination
Rect tool is a recent addition that made an appearance in the later versions of Unity 4. The circle in the center of the object acts as the Move tool and a quad created with four dots on the outside works similar to the Scale tool. Dot location will change position based on the camera angle.
In addition, the toolbar contains...