The backhand of the market price is to close the position with the latest price, and then open the position in the opposite direction to the previous position with the same number of hands.

Chinese mainland's futures contracts allow bilateral positions. That is, it is allowed to hold multiple positions and empty positions at the same time. Reverse opening refers to positions with the same number of positions and opposite directions.

Locking generally refers to an operation method in which futures traders open positions in the same amount but in the opposite direction, so that no matter where the futures price changes (rises or falls), the profit and loss of positions will not increase or decrease. It's a bit like the reverse opening above.

Hedging is hedging, which is generally the expected spot price trend of spot traders. They open positions in the futures market in the opposite direction and with the same number of lots.

Stop loss position should be determined by yourself.

You'd better ask the customer service of the futures company for these questions, or ask them some information about learning the basic knowledge of futures.