How to double jump? i just can jump once when it touch the ground.. help me guys =D

Questions & Answers
1

private bool jumping;
private bool sliding;
private bool wallHolding;
private bool stopSliding;

// Components
private PlayerPhysics playerPhysics;
private Animator animator;

// private GameManager manager;

void Start () {
	playerPhysics = GetComponent<PlayerPhysics>();
	animator = GetComponent<Animator>();
	//manager = Camera.main.GetComponent<GameManager>();
	animator.SetLayerWeight(1,1);
}

void Update () {

	// Reset acceleration upon collision
	if (playerPhysics.movementStopped) {
		targetSpeed = 0;
		currentSpeed = 0;

	}

    //player slash

    if (Input.GetButtonDown("slashing"))
    {
        animator.SetTrigger("slash2");
    }

    // If player is touching the ground
    if (playerPhysics.grounded) {
		amountToMove.y = 0;
		
		if (wallHolding) {
			wallHolding = false;
			animator.SetBool("Wall Hold", false);
		}
		
		// Jump logic
		if (jumping) {
			jumping = false;
			animator.SetBool("Jumping",false);
		}
		
		// Slide logic
		if (sliding) {
			if (Mathf.Abs(currentSpeed) < .25f || stopSliding) {
				stopSliding = false;
				sliding = false;
				animator.SetBool("Sliding",false);
				playerPhysics.ResetCollider();
			}
		}
		
		// Slide Input
		if (Input.GetButtonDown("seret")) {
			if (Mathf.Abs(currentSpeed) > initiateSlideThreshold) {
				sliding = true;
				animator.SetBool("Sliding",true);
				targetSpeed = 0;
				
				playerPhysics.SetCollider(new Vector3(10.3f,1.5f,3), new Vector3(.35f,.75f,0));
			}
		}
	}
	else {
		if (!wallHolding) {
			if (playerPhysics.canWallHold) {
				wallHolding = true;
				animator.SetBool("Wall Hold", true);
			}
		}
	}
	
	// Jump Input
	if (Input.GetButtonDown("Jump")) {

		if (sliding) {
			stopSliding = true;
		}
		else if (playerPhysics.grounded || wallHolding) {
			amountToMove.y = jumpHeight;
			jumping = true;
			animator.SetBool("Jumping",true);
			
			if (wallHolding) {
				wallHolding = false;
				animator.SetBool("Wall Hold", false);
			}
		}
	}
2

Sorry If I misunderstood,
There is a simple method how far I know.

For Single Jump:
You must have track that are you currently present on Ground or not. You can check with the setting up the bool (like isGrounded). This bool is false when you press the jump button or your collider is not touching the ground. When again you touch the ground your bool will be true.

For Double Jump:
You can place a counter for that ( I don’t know the correct approach for the same) . Now you have to check whether you are on ground and what the counter is.
Explanation:- For first jump the above ‘Single Jump’ logic is correct then for double jump you must check that your isGrounded bool must false and counter value must be one(because till now you have pressed jump button once). Now you are eligible to jump again ( Because condition of double jump is matching) now as with the jump button pressed again you again have to increment the counter so that if player want to make the triple jump they should not able to make that