CentiLeo is distributed as an archive via Download page. This archive has several folders for different Cinema versions. Each folder has all necessary plugin files and should be copied to the Cinema plugins folder.
Extract downloaded archive
To install CentiLeo for Cinema R23 you should copy CentiLeoR23 folder from downloaded archive to the plugins folder of Cinema 4D, e.g. to “C:/Program Files/Maxon Cinema 4D R23/plugins/” (or other custom plugins folder).
For older Cinema versions use the other CentiLeoRXX folder copy.
Run your Cinema 4D and select CentiLeo renderer
If CentiLeo doesn't show after installation
Update Cinema 4D build accordingly: S24.035+ R23.110+ S22.016+ and R21.115+ builds for latest Cinema versions.
Make sure supported GPU drivers are installed: NVIDIA Game Ready Driver 441.87+ or NVIDIA Studio Driver 441.66+ from here