Sport Gambling Torrents Can Someone Explain This Sports Gambling Thing To Me?

Can someone explain this sports gambling thing to me? - sport gambling torrents

I understand that spreading all aspects of sports games, with the exception of the item. I understand that it has something to do with the margin of a team to win for you to win the bet. But tell me, I will use on the Giants last week and the spread of 7 years. Since they won by only 3 of what it means, even if you bet on the Giants, would have nothing to gain and lose all the money? Can someone explain?