I had the option, but decided to get the big siren instead of remote start. (Garaged car)
Its very simple, you put it in neutral and you hit some odd button, and then get out, and it stays running after you turned the car off, then it will die, but once you go back out you hit another button on the alarm and it starts up, and will run for a while with the alarm on until you get in and turn the key to the on position.
Or something along the lines of that big complex process.