Your situation is different from the usual foreign trade business, it is cash sale. There is no need to sign a contract or go through foreign trade formalities. You pay foreign exchange through a bank account, and the bank can exchange it directly for you. The invoice issued by the other party is not from China. You don't need to know English either. As long as what you like is good, the introduction is appropriate, and you are not afraid of being cheated (I mean in case), just pay directly.