Because this is a fan-made project that uses the original game files, you won't find it on Steam or Origin. Here are the primary ways to find the :
Download the Rework 3.0 zip file and extract it using a tool like Copy the contents of the "Redux/Rework" folder.
The (often associated with the "Enhanced Rework" or "Redux" projects) is a major community-driven overhaul of the 2005 classic. It is designed to modernize the game with high-definition textures, improved lighting, and refined gameplay mechanics. Download Sources