In this recipe, you added an Animation Controller State Machine to the hero GameObject. The two animation clips you created (idle and jump) appear as states in the Animator window. You created a Transition from Idle to Jump when the JumpTrigger parameter is received by State Machine. You then created a second Transition, which transitions back to the Idle state after waiting 0.5 seconds (the same duration between the two keyframes in our Jump Animation Clip).
The player makes the character jump by pressing the spacebar. This causes the code in the PlayerControl C# scripted component of the hero GameObject to be invoked, which makes the sprite move upward on the screen and also sends a SetTrigger(...) message to the Animator Controller component for the Jump trigger.
The difference between a Boolean Parameter and a Trigger is that a Trigger is temporarily set to True. Once the SetTrigger(...) event has been consumed by a state transition, it...