I did this wrong three times in a game and ended up drawing an Estate instead of the other card that I was trying to topdeck. My intuition was "the first card I click will be on top, and the second card I click will be second in line", but the UI interprets as "the first card you click will be topdecked first and the second card will be topdecked second and end up on top." There are no numbers to indicate which order things will happen, or a pop-up to let you drag and drop to "top" and "bottom" like there is for other cards. After the first time this happened, I was like "okay, remember to do it right next time" and the second time, I couldn't remember what I did the first time, so reasoned through what I thought would be right, and got it wrong. And then I did it again. After the third time, I wrote it down, but this nearly cost me the game.