After it loads, it shows the intro which can be skipped with the button in the lower left corner. Then you're shown basic rules leaflet which is skipped by clicking the button hovering over it. Then press a button on the lower left to see racers' stats, then click the button hovering over it to get to the betting. Pick the bet type, then the racer(s) and hit the large yellow button under the pic. Then you get the choice whether to bet again (left button, up to three bets per race), or to watch the show.
The race seems to be composed out of three prerendered movies (excluding the intro): start (always identical), the bend where the panto horse falls, and the finish, where the variety starts. So far I've seen the victories of Jumbo, the US duo, the whipping chick in leather and the biker horse dude.