well if and i do mean IF i am right about this, you would have to use your DvD Remote to pick one of the two choice's that would appear on screen.
i had the DvD in which had this on it, but i had only Rented it, and i did not use the disc that had this on it.
so in other words, ask someone who isnt me.
Yeah, there's a "Choose Your Fate" type page that pops up, and you can pick Heads or Trail, IIRC. There may be a regular Theatrical version of the movie on the DVD. It's been a while.
BTW..as a precaution..
Spoiler:
if you pick the first fate, which is the roller coaster, everyone survives and the movie is OVER! It's TERRIBLE..because one becomes a bohemian..one ends up being gay..bah.