How to set movement speed in meters per second to the Standard Assets' ThirdPersonCharacter?

Hello,

I'm looking at the ThirdPersonCharacter in Standard Assets, and I see the walking speed is determined in the following method:

         public void OnAnimatorMove()
         {
             // we implement this function to override the default root motion.
             // this allows us to modify the positional speed before it's applied.
             if (m_IsGrounded && Time.deltaTime > 0)
             {
                 Vector3 v = (m_Animator.deltaPosition * m_MoveSpeedMultiplier) / Time.deltaTime;
 
                 // we preserve the existing y part of the current velocity.
                 v.y = m_Rigidbody.velocity.y;
                 m_Rigidbody.velocity = v;
             }
         }

I don't understand what the Animator.deltaPosition property is, also after reading the documentation that says:

Gets the avatar delta position for the last evaluated frame.

I would like to be able to set the maximum walking speed in meters per second. How would I do it?

Thank you in advance for your help.