Ps4 controller not working

Hey everyone, so I'm trying to use my ps4 controller on Forza 5 and it just doesn't seem to work. I'm playing Forza on my Pc and I've downloaded it from the Xbox game store. The controller doesn't seem to be registered at all with forza as if I plug it out, it doesn't show the controller disconnected sign. But the controller works every where else so I'm not sure what's wrong.