Copy the cracked content from the /Crack directory to your main game install folder.
Given the age of this content (2014-2015), many re-uploads online are fake, filled with malware, or corrupted. If you are looking for archival or research purposes, here are markers of an authentic release: Assassins.Creed.Unity.Update.v1.5.Proper-RELOADED Pc
There are several reasons why collectors and modders still seek out : Copy the cracked content from the /Crack directory