First of all, you need to open an account and have an account in the exchange in the name of a member of the futures company. Then use the funds under this account to buy and sell contracts on various varieties. Simply put, you think cotton should go up. Just buy a contract for this cotton. He goes up, you make money. You think she's going to fall. You just buy a contract that she's going to lose. He really fell. You made money, too. It's that simple. More specific and detailed related knowledge, you can add me to communicate.