A Part is a single component of a larger assembly. Within the Assembly workbench, a part is either a part of the Part Design workbench, or a 3D entity whose geometry is contained in a model.
•Select Insert 
New Part, or in the specification tree, select the desired component and click the 
New Part icon. The command is also available in the Product Structure Tools toolbar.
•If geometry exists in the assembly, the New Part: Origin Point dialog box is displayed, proposing two options to locate the part:
•Click Yes to locate the part origin point on a selected point, on another component for example.
•Click No to define the origin point of a component based on the origin point of the parent component.