If you expect the price to go up and operate in the direction of bulls, then you open the position. At a certain price point, you need to close your position and take a long position, thus completing a long position.
If you expect the price to fall in the short term, then you will establish a short position. At a certain price, you need to close the position and close the short position to complete the short position.
The object of closing the position is to open the position today and close it on the same day. Futures are T+0 transactions, and positions can be closed on the day of opening. Some varieties are free today, and only the opening fee is charged, but if you keep the warehouse until the next day, you need to pay the closing fee.
Those questions behind you are really hard to understand.
There must be ups and downs when there is a transaction. Contracts of the same variety in different months may rise and fall in different directions, and futures reflect forward prices. In practice, there is indeed a deviation in the contract direction of the same variety in different months, but this is a short time, and the overall general trend is still the same.