Is this the right way to do Double jumping? C#

I have tried to make a double jumping feature in my game, but it wont work. My game is on a spherical world and here is my code:

if (Input.GetButtonDown (“Jump”) && grounded && jumpCount < 2){
{
rigidbody.AddForce(transform.up * jumpForce);
jumpCount = jumpCount + 1;
}
}

	if (grounded = true) {

		jumpCount = jumpCount - jumpCount;
	}

	grounded = false;
	Ray ray = new Ray (transform.position, -transform.up);
	RaycastHit hit;

	if (Physics.Raycast (ray, out hit, 1 + 0.1f,  groundedMask)) 
	{
		grounded = true;
	}
}

Can someone fix my code, or inform me in what i am doing wrong so i can fix it, i am a beginner at Unity. Thanks :smiley:

There is this tutorial by Mike Geig talking about double jumping: