Hmmm...it will be a bit tricky as I don't exactly remember what was called what. Anyway, I will give it a shot.
1. Download the mod in zipped format.
2. Unzip or UnRAR it. You will find a file with an extension .mpm (I think that what the extension was.)
3. Copy and paste the .mpm file into the directory where Max Payne is installed. The path might be something like this: "C:/Program Files/Remedy/Max Payne", where C: being your default directory.
4. Now close all folders and run Max Payne.
5. A small configuration window will open up.
6. The last option in that window is "Choose Custom Game". Before installation of the mod, it was greyed out, but now you can clcik on it, scroll down the drop=down box to select KungFu3.0 and hit apply.
7. The game will launch in KungFu mode.
I have listed the steps according to what I could recall. But my memory could have failed me. So use some intution while following the steps. The steps are 95% accurate.