How to i use get key to use the turn?

Questions & Answers
1

I need to make it so it only turns when i press x plz help.

using UnityEngine;
using System.Collections;

public class Lerp180Left : MonoBehaviour
{
	public Vector3 axis = new Vector3( 0, 1, 0 );
	public float degrees = 90f;
	public float timespan = 1f;

	private float _rotated = 0;
	private Vector3 _rotationVector;

	public void Start()
	{
		axis.Normalize();
		_rotationVector = axis * degrees;
	}

	public void Update()
	{
		_rotated += degrees * (Time.deltaTime / timespan);
		if ( degrees > _rotated )
			transform.Rotate( _rotationVector * (Time.deltaTime / timespan) );
	}

}
2

void Update() {
if (Input.GetKey(KeyCode.X))
{
_rotated += degrees * (Time.deltaTime / timespan);
if (degrees > _rotated)
transform.Rotate(_rotationVector * (Time.deltaTime / timespan));
}
}

ScriptReference - Input

ScriptReference - Input.GetKey