Click theicon in the top bar > Object Type Groups in the Data Model section.
Click Create Object Type Group.
Enter a name for the object type in the Name field.
Optional: Enter a brief description of the object type group in the Long Name field, which will appear below the object type when editing it. The Create Object Type Group page.
Click Create to display the Related Object Types section.
In the field in the Related Object Types section, enter the name of the object type you want to add or select it from the dropdown menu. Continue to add more object types as needed.A new Object Type Group. After clicking Create, the Related Object Types section is displayed.