You are correct. He doesn't know how tariffs work. He thinks the foreign government or country pays them, which of course they do not. But his base doesn't understand that, either, so he can bs them some more.

China's response to his application of tariffs was to slap tariffs on U.S. goods, specifically goods from parts of the U.S. that supported Trump. So China has retaliated against U.S. farmers by dramatically reducing their purchases of U.S. soybeans, and on other farmers by slapping tariffs on U.S. whiskeys, among other products. I don't know if those supporters of Trump recognize that, or not. Plus Trump is using price supports to pay off farmers, so at least some of the effect is being mitigated.