hisense h9f

So i recently bought a Hisense H9F and im trying to enable 4K @ 60hz but I just cant figure it out. I have an R9 390 with up up date drivers. Im using a Displayport 1.2 to HDMI 2.0 adapter. Im running an HDMI 2.0 cable from my tv to the adapter which is plugged into the DP 1.2 on my GPU. for...