Answer supplement 1\ The physical object corresponding to the contract.
I think your understanding of this letter is correct. Contracts are based on physical objects, but it doesn't mean that there will be many goods as many contracts. Simply put, when you sell a contract, you don't mean that you have to have the goods.
2\ Why does the location change? That is, the change of position is the change of contract, and then it is actually the change of body.
In futures trading, there will be changes in opening and closing positions, which have nothing to do with contracts and targets.