pivot center of a assembled parts

Hi

How do I change the pivot point center of a assembled parts?

I want the pivot center to be at the base of the group, not the exact center.

It says What's New in SOLIDWORKS 2017

Pivot point snapping lets you accurately locate a model's pivot point on the model surface.

To place the pivot point:

  1. Click Object Manipulation Tools > Pivot .
  2. Hold the Ctrl key.

How to find the Object Manipulation Tools?

Thank you..

SolidworksGeneral