The reason nobody has replied to you is that you haven't replied to deaddog. He's given you a nice script, for which you haven't thanked him. Nor did you thank Komuna. You haven't told us anything about what happened when you tried the script. What do you mean "it doesn't work"? Be more specific. What are you trying to achieve? What did you do? What happens? How do you know it isn't working?
Before we help you (which we do as a favour, nobody is obliged to help you so no more comments about a lack of patience, please) you have to help yourself. I suggest you start by improving your attitude.
/bollocking
I've had a quick look at the tute and I found this
the global variable 'laser_pos' will contain the position of where the notional laser is hitting the ground, at any point in time.
which answers your question. You don't have to understand the code to use it.
Edit: if you're not sure how to use snYpir's script read the tute again, concentrating on the text and not worrying too much about the code. If you're still stuck, ask again here.