How to get score point if i click a rock in 3d

Hi
I try to make a 3d clicker and i don’t now how to make score system

I don’t have any skills in C #
and all I have
it’s Raycast on the camera

151124-script.png

i just need a help or tutorial how to do it

(it’s my first game in unity)

Use a method called

void OnMouseDown()
{
    //The object has been clicked on, it must have a box collider!
}

Thx it’s works!
151155-onemousedown.png

But i found tutorial how to make score system
151156-score-system.png

and it works so much that I don’t know how to convert the code to add points only after clicking the rock