Light switch dimmer

I am replacing a old turn knob dimmer with a new dimmer. The new dimmer has 4 wires, a red, a white, a black and a green.

My old one is wired up with two red wires and a black wire, in the junction box there’s two white wires and a ground.

How should I wire the new dimmer up to a junction box that has two white wires and a ground?