Right click in windows, got to new, choose any file, i usually go with txt file, and rename it something.script and leave the txt part out. Then open it with whatever you use to edit script. I prefer a freeware app called notepad2. I would look at the autosiren script(that may not be the exact name but you get the idea) and change out the variables to point to your airhorn rather then the siren. Not sure I explained that very well, but do you get the idea?