If you use the Set Designer "Sets and Locations", they will be delivered in .LIB4D format. This video describes how to install and use it in Cinema 4D.
The .LIB4D format is one of my favorite features of Cinema 4D as it is easy to create a local database of models and materials. And then easy to share and move these libraries to other systems.
If you have any questions, please go to the forum or leave them directly in the YouTube video.