Thanks for the question! So here, remember that we’re told that T is assigned a higher-numbered parking space than S. But in your diagram, assuming it goes left to right 1-6, you’ve assigned T a lower parking space than S (T is in 1, but S is in 4). So that violates the hypothetical we’re given. T has to go after S; that’s what it means for T to have a higher number.
Hope this helps! Feel free to ask any other questions that you might have.