If you are attempting to use a .zip file for modding or installation, common community steps from guides on Steam include:
The full mod adds roughly 36 GB, bringing the total installation size to nearly 50 GB. System Requirements: RAM: 2 GB minimum; 4 GB recommended. GPU: NVIDIA GeForce 8800GTS / ATI Radeon HD 4850 or better. OS: Windows XP/Vista/7/8/10. Installation & Management File: Resident Evil 4 - Ultimate HD.zip ...
For those looking for the save locations instead of the classic edition, they are typically found in your Steam userdata folder under ID 2050650 . If you are attempting to use a
Always back up your bin32 and bio4\etc folders before modifying files. File: Resident Evil 4 - Ultimate HD.zip ...
Extract the .zip contents (using tools like 7-Zip) directly into the main Resident Evil 4 installation folder.