Got to believe it would be fairly simple as it's just two wires that go to the grid on the window. Get a switch and figure out where you want to mount it. Provide it with switched power and you're good to go. Might want to find out what size fuse the quads use for their defrost circuit so you have an idea what you'll need for supply current.
Sounds like you got a great deal!
Sounds like you got a great deal!