YOU ARE LOST IN A PLACE OUTSIDE OF REALITY.
In the midst of a cataclysm, you suddenly stumble over something and fall into a place that looks like an underground living space. After a while, you begin to realize that you are not underground at all, and then you will be able to compare all the evidence... and to realize that there is something worse than bombs falling from above.

Install the file.
Unzip the archive to your \User\Documents\Teardown\mods disk or to the mods folder in the root folder of the game.
"If there is no mods folder, create one."
Enjoy.