You can't sell it in the futures market if you buy the spot.
Simply put, the products in the futures market are all in the warehouse of the exchange, and you don't need your spot exchange. You can only trade contracts in the futures market, that is, make a forward contract with others in the market, order a long contract and a short contract.
If it is not a legal person, it can't wait until the contract expires before delivery. Individuals can only make a profit by making a price difference before the contract expires. For example, in May 2009, the current price of the bean contract was 3,259 yuan, and you opened an empty order. After a few days, it falls to 3 100 yuan, and you can make a profit by closing your position (3259-3100) *10 =1590 yuan.