I am assuming you are on Linux.
If you are, just run:
man patch
and it will tell you all about patch files.
In case your knowledge is VERY limited, let me explain patch files a bit more.
Patch files are quick ways to apply changes in code to an existing bit of code that you already have.
This means that you have to re-compile whatever it is you are patching, you cannot simply place it in a directory and have it working.
Another good alternative is our friend, the
hivemind.

All this being said, I do believe this topic belongs in the "Troubleshooting" section.
Hope this is what you needed,
Whales