This video shows you how to save static assemblies to the home builder library. Static assemblies are assemblies that don’t change in size so this will show you have to save manufacturer specific ranges, range hoods, refrigerators, dishwashers, sinks, and cooktops.
Link to written article - https://creativedesigner3d.com/2021/01/19/saving-static-assemblies-to-blender/
Link to full training series - https://creativedesigner3d.com/2021/01/12/essential-training-series-extending-the-home-builder-library/
Extended Asset Library - https://creativedesigner3d.com/extended-asset-library/