Closing a position refers to selling the originally bought contract or buying the originally sold contract.

Suppose the soybean meal is currently 3000, and you make 10 soybean meal at 3000.

Make up the position: the price has fallen to 2900, and you think it's just a callback. In order to reduce the cost of holding positions, buying 10 lot of soybean meal at 2900 means covering positions.