To install you need image editor tool, i used Alci's IMG Editor. 
Open it, navigate to your game folder, open models folder then player disc image file.
Search for hoodyablack.txd, click import (remove if exists) and replace it with new file, click save.
Also if you want to replace other color version of hoody you have to rename it to the base version,
for example if you want to import this new file over green hoody then you name it like hoodyagreen instead of hoodyablack.
I haven't tested it, but i think it should work. And you only need to replace txd file, don't touch dff.