Single bets are bets that cover one race- for example, a win or a place.
The Tote Win and Place bets are the simplest bet you can place. Just pick a horse to win or place in a race.
Other more exotic type bets, such as the Tote Exacta or Tote Trifecta can yield big wins from a relatively small stake. To win these you must pick the first two, or first three horses home in the correct order.