Maybe i am forgetting something from one of the beginning tutorials, but I can't for the life of me understand why pressing W and S cause the walk parameter value to change from 1 to -1 respectively. The CharacterMovement script doesn't even have an Input.GetButtonDown to recognize that I am pressing W or S. Also, the character itself is moving along the X (or Z) axis; he is not traveling vertically. To sum this question up, I guess what I'm asking is WHY does the CharacterMovement script even work? There is something fundamental about this script that I am just not understanding.
The W and S keys are using the Vertical axis from the input manager. By default the WASD keys use the Horizontal/Vertical axis inputs, same for the arrow keys and usually the joystick on just about any supported controller.