Add point on click of cube?

Hi everyone, I am creating a game and I have become a bit stuck on this bit. Basically, I want it so that when you click on a cube it adds a point. I then want a score box at the top of the screen showing how many points the player has got so far. I’m a bit of a novice to programming so any help would be greatly appreciated!

public class ClickableCube : MonoBehaviour{ // Attach this script to your cube. It also needs a collider attached.

     public int timesClicked; // this counts how many times the cube has been clicked

     void OnMouseOver()  // this is called once per frame on any object that has a collider and is pointed at with the mouse
     {
           if(Input.GetMouseButtonDown(0)) // if it's not only pointed at, but also clicked
           {
               timesClicked++;  // increase the click counter variable
           }
     }
}

public class Playerscore{ // this class shows the score on the screen. attach it to any object in the scene.

          public ClickableCube cube;  // this stores a reference to your cube. Drag the cube into this field in the inspector to assign it.

          public Rect scoreRect = new Rect(Screen.Width-200, 0, 200, 50)  // this is a rectangle in the top right corner of the screen

          void OnGUI()
          {
                GUI.Label(scoreRect, "Score: " + cube.timesClicked);  // this draws the score from the cube into the rectangle
          }

}

That said, I think you should work through some basic tutorials.