How can I fix this error ? Please help ! BCE0020: An instance of type 'UnityEngine.Rigidbody' is required to access non static member 'velocity'

private var moveForward : float = 0;
private var moveSideways : float = 0;
var jumpForce : float = 3;
var moveSpeed : float = 20;

function FixedUpdate () {
moveForward = Input.GetAxis("Vertical") * moveSpeed * Time.deltaTime;
moveSideways = Input.GetAxis("Horizontal") * moveSpeed * Time.deltaTime;

rigidbody.velocity = transform.TransformDirection(Vector3(moveSideways,Rigidbody.velocity.y,moveForward));
transform.Rotate(Vector3(0,Input.GetAxis("Mouse X"),0));

if (Input.GetButtonDown ("Skok")){
 rigidbody.velocity.y += jumpForce;
}

}

On line 10, change ‘Rigidbody.velocity’ to ‘rigidbody.velocity’. Upper case is the class. Lower case is a shortcut to get the component.