Align to Normal
Align selected objects to the normal of another object (for example, a face).
If the object that you want to align has construction
            history, you need to select Edit > Collapse Construction.
        - 
                Select one or more objects.
                Note:
- To select multiple objects, use box selection or hold down Ctrl while clicking the objects.
 - To chain select in the Model Browser, hold down Shift while clicking the names of the objects.
 
 - 
                Open the Move tool:
                
- Press W.
 - From the Home tools, click the
                                Move icon.

 
 - 
                In the Control Panel, select Align to Normal.
                In alignment mode, the manipulator disappears, and intersecting red, green, and blue lines are displayed to represent the x, y, and z axes. The position of the alignment axes depends on the first selected object.
 - 
                Press Ctrl and select objects to align to the normal of
                    another object.
                Tip: You can align to a face and orient the object to that face.
 - Right-click and mouse through the check mark to exit, or double-right-click.