Lumion is the key of the fast exterior/interior rendering. You don't need anything as an object in your scene. You only need walls, Lumion has a great archive about peoples, furniture, vehicles, decorative objects, etc.
You don't need to material archive for renders because Lumion had a great deal with Poliigon and other texture creators. Also, It have own texture archive inside. In the Pro version, you can reach thousands of materials and object.
In this tutorial, we showed you how to create terrain, and how to change textures of models and how to prepare a scene for renderings.
There is a great free alternate of it - Twinmotion