A bit more difficult than usual. Go inside the RAF folder, then drag what's in there into ItzWarty's RAFManager. Please note that you will be asked if you want the files to apply to the Judicator or the Kayle folder - choose Kayle each time. The Judicator folder is a leftover that older patches use, and the skin may not display properly if you choose it.
The deploy folder goes into League of Legends/rads/projects/lol_air_client/releases/(whatever number's there and happens to be highest)/
As a note, if you think you might want to do several install/uninstalls, you can move the Animation folder out of the RAF folder while patching. It is not mandatory at the moment, but I included it so that the skin will work in case of future patches that change Kayle's animations.