Selecting objects in a scene can be done in 2 ways - In the Step Hierarchy or directly within the scene.

The step hierarchy window displays the content within your scene and allows you to select, organize, add and remove parts of an object from your scene. 

Note:

• Holding "Ctrl" selects/deselects multiple objects at a time.
• Double clicking on the level/part within the Step hierarchy automatically zooms that selection into frame.
• Right clicking on selection launches additional capabilities for object control.