There will be four doors revolving around the central hub. You have one door so far, and you will make three instances of the door to complete the wheel.
 open start_door_clone.max in the \startup folder.
 open start_door_clone.max in the \startup folder. 
            Before you clone the door, you center its pivot point so it will rotate around the origin.
 select the door.
 select the door. 
             Hierarchy panel. On the Adjust Pivot rollout, click to turn on Affect Pivot Only.
 Hierarchy panel. On the Adjust Pivot rollout, click to turn on Affect Pivot Only. 
Viewports display the door's pivot point, which is at the base of the door and at the side of the cylinder.


This right-click menu is called the quad menu. You can use it to access tools from the toolbar and command panel for quicker workflow. You can even customize it to keep your favorite tools right under your fingertips.

This moves the pivot point for the door to the origin, (0,0,0), which is also the pivot point for the cylinder.
 Adjust Pivot rollout, click Affect Pivot Only to turn it off again.
 Adjust Pivot rollout, click Affect Pivot Only to turn it off again. 

 (Angle Snap), if it isn’t on already.
 (Angle Snap), if it isn’t on already. 
               On the toolbar, the Angle Snap button highlights.

Holding down Shift as you transform an object serves as a quick way to clone the object.

Now there are four doors within the enclosure.
 
                  Clone the door to create a wheel of doors.
Change the hub back into a cylinder:
 Select the hub (Cylinder01), and then on the
 Select the hub (Cylinder01), and then on the  Modify panel change its Sides value to 12.
 Modify panel change its Sides value to 12.