Load your counters in. Then, begin! Tug at the wheels to get all your counters down to the trays at the bottom as quickly as possible, at the same time as your opponent is doing the same thing. Use brute strength to move the wheels the way *you* want them to move, while your opponent uses brute strength to do the same thing. And hurry up!
Yes, the link above says that you should take turns to move the wheels, and that's how parents and friends' parents told me I was supposed to play it, but I was unconvinced. For one thing, it didn't seem as much fun as my version. Also, the blurb on the box seemed to support my way of playing the game: it described it as a "strategy" game, and "strategy" quite obviously meant tugging at wheels trying to outdo your opponent. I guess I didn't really know what the word meant, and I was relying on the sound of the word - the "str" beginning must have sounded like "strength", "struggle" and "strain" to me.
That, and that's what I'd have *liked* it to mean.