Launch DAZ Studio
In the content library tab, right-click on My DAZ 3D Library.
Select "Browse to folder location".
The My DAZ 3D Library folder should open...
In the Destroy file you downloaded, unpack the three folders data, Destroy!, and Runtime to the folder My DAZ 3D Library
Switch to DAZ, right click and refresh the My DAZ 3D Library folder.
Destroy! is now available in
MY DAZ 3D Library > Destroy!