First, open more than one position. If you open multiple positions in one hand and make a deal, that is, you buy a futures contract, then you can make a deal only if a seller sells it to you.

So, the possible situation is:

(1) The seller has no position and has opened a new short position;

(2) The seller has also opened many orders before, and there are many positions. Now it is necessary to close the position in the opposite direction, that is, sell it. So there are many warehouses in the plain at this time, and the corresponding operation is selling.

I won't say much about the same reasons for opening positions.

Second, pay attention to leveling multiple positions, that is, leveling the original multiple positions, and the operation is selling: it used to be buying, but now it is naturally selling.

Close the short position, that is, close the original short position, the operation is to buy: it turned out to be selling, and now closing the position is naturally buying.