To nest families in another family, create or open a host (base) family, and then load and insert instances of one or more family types into it. The base family can be a new (empty) family or an existing family.
To create a family with nested components
Create or open a family into which you want to nest a family.
In the Family Editor, click Insert tabLoad from Library panel (Load Family).
Select any families that you want to nest, and click Open.
Click Create tabModel panel (Component).
In the Type Selector, choose the component type that you want to nest.
Click in the drawing area to place the nested component in the family.
If necessary, repeat steps 4-6 to nest components in the family.