Building a position is a professional term in futures trading, also known as "opening a position". It involves the behavior of investors buying or selling futures contracts for the first time. Opening a position can be divided into two basic types based on the trader's expectations for the market:

First, opening a position by buying, that is, investors expect the market to rise and place an order to buy futures contracts, indicating that they are bullish on the index. This operation is to buy a long order, which represents a bullish stance.

Secondly, sell to open a position. On the contrary, investors believe that the market will fall and place a short order to buy, that is, short futures, which means shorting the index. This is a sell contract, indicating a bearish expectation.

In futures trading, the entire process can be summarized as opening a position, holding a position and closing a position. When investors place an order to buy or sell a futures contract, they are actually entering into a forward delivery agreement. Most traders will not stick to the last delivery day, but will trade in the opposite direction (i.e. close positions) at the right time to offset the original contract, thereby ending the transaction and avoiding the obligation of physical delivery. Contracts that are not closed during the trading process are called open positions. Traders can choose to close their futures position by closing the position, or hold it until the delivery date for physical delivery. Therefore, whether it is a buy position or a sell position, it is all about realizing traders' expectations in the futures market and managing their positions through appropriate strategies.