How to use a button to trigger an Animator Parameter

I have a game main menu with a button called PlayButton. What the game should do is when the button is pressed, play a "FadeToGame" animation(animation fades objects on screen to reveal game behind). However, I don't know how to code it so that when the button is pressed, it activates the GameControl animator trigger.

How do I code the button so that it activates the trigger?