How to make animator do run/walk animations

Questions & Answers
1

I have some FPS arms and all the animations set up in an ANIMATOR CONTROLLER. How can I check to see if the person in holding down shift, the run animation plays? Also if you know how can I make it so when they push shift their speed goes up?
C# if possible

2

You would want to do something like this inside update.

if (Input.GetKeyDown(KeyCode.LeftShift)) {
//do setup for increased player speed
}

if (Input.GetKeyUp(KeyCode.LeftShift)) {
//do setup to return to player baseline speed/animation
}