Locate your .minecraft folder
	If you do not know where this is, press start > run and type %appdata%/.minecraft
	Hit enter
	If this does not work search for a solution on the internet

Go into the bin folder

Open minecraft.jar with an archive program such as winrar

Drag all the class files inside the minecraft folder, from this download, and copy and replace them into the minecraft.jar

Delete the META INF folder inside the minecraft.jar

Mod installed, have fun.