Excuse this old head sportz, but I can't quite get it around how this comp. would play out [?]

OK, we have a stable of horses and then what? We add up the winnings of our stable? What about if we have some lightly raced horses set for certain goals and others have a go for [short term] cash stable?

How does it pit one player against another when really in the end it's just horses against horses and luck of how the original draw [regardless of how fair] pans out?