Check if player is grounded and play a sound 1 time

Questions & Answers
1

How i can make that detect if the player is grounded and play the footstep audio 1 time? because it is repeating the sound all the time when i am grounded

if (m_CharacterController.isGrounded)
{
       FootstepSounds footstep;
       footstep = GetComponentInChildren<FootstepSounds>();
       footstep.FootStep(); //PLAY THE SOUND
}
2

Lots of way to do it, like using OnCollisionEnter and checking the tag of the other object, but you can try this:
Declare a variable to store the previous state

private bool wasGrounded = true;

And then just do

 if (m_CharacterController.isGrounded && !wasGrounded)
 {
    GetComponentInChildren<FootstepSounds>().FootStep(); //PLAY THE SOUND
 }
  wasGrounded = m_CharacterController.isGrounded;