In the futures market, it is allowed to sell the position when there is no position in hand, and then buy the position at an appropriate time according to the trading strategy, which is liquidation.
When the market is in a downward trend, the way to make a profit is to sell first and then buy and close the position.
In the upward trend of the market, the way to make a profit is to buy first and then sell and close the position.
The key to profit here is to correctly grasp the state of the market and understand the language of the market.
As for how to interpret the language of the market, The Law of Market Behavior translated by E-Business School is the first one, which is the core of Mr. joe roth, an American trading master, investor and trading training expert. He is also the author of the Rockwell Hawke Trade Act, which has also been published. It's worth reading and benefiting a lot.