The assets was created primarily to be used as a complement to scenes, decoration, and is readily usable. To use it, there is no secret. Extract the files from the .ZIP folder, and within your program/scene, simply import the desired file from the folder. Remember that in addition to the .Blend format, .DAE, .OBJ, and .FBX formats are also included. All files already have the correct topology and UV and are optimized for realistic and optimized uses, but feel free to change some characteristics according to your creative freedom.