Need help making my character jump (C#) (Unity)

[manlykeweaver465]

public class PlayerMovement : MonoBehaviour {
	public float speed = 900f;

	public Rigidbody2D Rgb;

	// Use this for initialization
	void Start () {
		Rgb = GetComponent<Rigidbody2D> ();
	}

	// Update is called once per frame
	void Update () {
		float Haxis = Input.GetAxis ("Horizontal") * speed * Time.deltaTime;

		Vector2 Move = new Vector2 (Haxis, 0);
		Rgb.velocity = (Move * speed);

	}
}

Okay so I've got the movement of my character sorted but despite everything i try i can't seem to make my character jump, any help will be appreciated  .